diff --git a/Makefile b/Makefile
index d41b81a2..19530407 100644
--- a/Makefile
+++ b/Makefile
@@ -221,8 +221,8 @@ endif
 endif
 
 # convert "include/tccdefs.h" to "tccdefs_.h"
-%_.h : include/%.h tests/misc/c2str.c
-	$S$(CC) -o c2str.exe $(filter %.c,$^) && ./c2str.exe $< $@
+%_.h : include/%.h conftest.c
+	$S$(CC) -DC2STR $(filter %.c,$^) -o c2str.exe && ./c2str.exe $< $@
 
 # target specific object rule
 $(X)%.o : %.c $(LIBTCC_INC)
diff --git a/arm-gen.c b/arm-gen.c
index 3f432d85..5c44b8e0 100644
--- a/arm-gen.c
+++ b/arm-gen.c
@@ -141,6 +141,21 @@ enum {
 #define USING_GLOBALS
 #include "tcc.h"
 
+ST_DATA const char *target_machine_defs =
+    "__arm__\0"
+    "__arm\0"
+    "arm\0"
+    "__arm_elf__\0"
+    "__arm_elf\0"
+    "arm_elf\0"
+    "__ARM_ARCH_4__\0"
+    "__ARMEL__\0"
+    "__APCS_32__\0"
+#if defined TCC_ARM_EABI
+    "__ARM_EABI__\0"
+#endif
+    ;
+
 enum float_abi float_abi;
 
 ST_DATA const int reg_classes[NB_REGS] = {
diff --git a/arm64-gen.c b/arm64-gen.c
index 4ce46e6d..feff7415 100644
--- a/arm64-gen.c
+++ b/arm64-gen.c
@@ -50,6 +50,10 @@
 #include "tcc.h"
 #include <assert.h>
 
+ST_DATA const char *target_machine_defs =
+    "__aarch64__\0"
+    ;
+
 ST_DATA const int reg_classes[NB_REGS] = {
   RC_INT | RC_R(0),
   RC_INT | RC_R(1),
diff --git a/c67-gen.c b/c67-gen.c
index 3f963617..a1c1476c 100644
--- a/c67-gen.c
+++ b/c67-gen.c
@@ -114,8 +114,12 @@ enum {
 #define USING_GLOBALS
 #include "tcc.h"
 
+ST_DATA const char *target_machine_defs =
+    "__C67__\0"
+    ;
+
 ST_DATA const int reg_classes[NB_REGS] = {
-    /* eax */ RC_INT | RC_FLOAT | RC_EAX, 
+    /* eax */ RC_INT | RC_FLOAT | RC_EAX,
     // only allow even regs for floats (allow for doubles)
     /* ecx */ RC_INT | RC_ECX,
     /* edx */ RC_INT | RC_INT_BSIDE | RC_FLOAT | RC_EDX,
diff --git a/conftest.c b/conftest.c
index f3b6ea65..4a221d3f 100644
--- a/conftest.c
+++ b/conftest.c
@@ -1,3 +1,173 @@
+/* ----------------------------------------------------------------------- */
+#if C2STR
+
+/* with -D C2STR: convert tccdefs.h to C-strings */
+
+#include <stdio.h>
+#include <string.h>
+
+/* replace native host macros by compile-time versions */
+const char *platform_macros[] = {
+    "__i386__",             "TCC_TARGET_I386",
+    "__x86_64__",           "TCC_TARGET_X86_64",
+    "_WIN32",               "TCC_TARGET_PE",
+    "__arm__",              "TCC_TARGET_ARM",
+    "__ARM_EABI__",         "TCC_ARM_EABI",
+    "__aarch64__",          "TCC_TARGET_ARM64",
+    "__riscv",              "TCC_TARGET_RISCV64",
+    "__APPLE__",            "TCC_TARGET_MACHO",
+    "__FreeBSD__",          "TARGETOS_FreeBSD",
+    "__FreeBSD_kernel__",   "TARGETOS_FreeBSD_kernel",
+    "__OpenBSD__",          "TARGETOS_OpenBSD",
+    "__NetBSD__",           "TARGETOS_NetBSD",
+    "__linux__",            "TARGETOS_Linux",
+    "__SIZEOF_POINTER__",   "PTR_SIZE",
+    "__SIZEOF_LONG__",      "LONG_SIZE",
+    0
+};
+
+int isid(int c)
+{
+    return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')
+        || (c >= '0' && c <= '9') || c == '_';
+}
+
+int isspc(int c)
+{
+    return (unsigned char)c <= ' ' && c != 0;
+}
+
+int main(int argc, char **argv)
+{
+    char l[1000], l2[1000], *p, *q, *p0;
+    FILE *fp, *op;
+    int c, e, f, s, cmt, cmt_n;
+    const char *r;
+
+    if (argc < 3)
+        return 1;
+
+    fp = fopen(argv[1], "rb");
+    op = fopen(argv[2], "wb");
+    if (!fp || !op) {
+        fprintf(stderr, "c2str: file error\n");
+        return 1;
+    }
+
+    cmt = cmt_n = 0;
+    for (;;) {
+        p = l;
+    append:
+        if (fgets(p, sizeof l - (p - l), fp)) {
+            p = strchr(p, 0);
+            while (p > l && isspc(p[-1]))
+                --p;
+            *p = 0;
+        } else if (p == l)
+            break;
+
+        /* check for continuation */
+        if (p > l && p[-1] == '\\') {
+            p[-1] = ' ';
+            goto append;
+        }
+
+        /* count & skip leading spaces */
+        p = l, q = l2, f = 0;
+        while (*p && isspc(*p))
+            ++p, ++f;
+
+        /* handle comments */
+        if (p[0] == '/' && cmt == 0) {
+            if (p[1] == '*')
+                cmt = 2;
+            if (p[1] == '/')
+                cmt = 1;
+        }
+        if (cmt) {
+            fprintf(op, "%s", l);
+            if (++cmt_n == 1)
+                fprintf(op, " (converted, do not edit this file)");
+            fprintf(op, "\n");
+            if (cmt == 1)
+                cmt = 0;
+            if (cmt == 2) {
+                p = strchr(l, 0);
+                if (p >= l + 2 && p[-1] == '/' && p[-2] == '*')
+                    cmt = 0;
+            }
+            continue;
+        }
+
+        if (f < 4) {
+            do {
+                /* replace machine/os macros by compile-time counterparts */
+                for (e = f = 0; (r = platform_macros[f]); f += 2) {
+                    c = strlen(r);
+                    /* remove 'defined' */
+                    //e = memcmp(p, "defined ", 8) ? 0 : 8;
+                    if (0 == memcmp(p + e, r, c)) {
+                        p += e + c;
+                        q = strchr(strcpy(q, platform_macros[f + 1]), 0);
+                        break;
+                    }
+
+                }
+                if (r)
+                    continue;
+            } while (!!(*q++ = *p++));
+            /* output as is */
+            fprintf(op, "%s\n", l2);
+            continue;
+
+        } else {
+            s = e = f = 0, p0 = p;
+            for (;;) {
+                c = *p++;
+
+                if (isspc(c)) {
+                    s = 1;
+                    continue;
+                }
+                if (c == '/' && (p[0] == '/' || p[0] == '*'))
+                    c = 0; /* trailing comment detected */
+                else if (s && q > l2
+                    && ((isid(q[-1]) && isid(c))
+                        // keep space after macro name
+                        || (q >= l2 + 2
+                            && l2[0] == '#'
+                            && l2[1] == 'd'
+                            && f < 2 && !e
+                            )))
+                    *q++ = ' ', ++f;
+                s = 0;
+
+                if (c == '(')
+                    ++e;
+                if (c == ')')
+                    --e;
+                if (c == '\\' || c == '\"')
+                    *q++ = '\\';
+                *q++ = c;
+                if (c == 0)
+                    break;
+                p0 = p;
+            }
+            /* output with quotes */
+            fprintf(op, "    \"%s\\n\"%s\n", l2, p0);
+        }
+    }
+
+    fclose(fp);
+    fclose(op);
+    return 0;
+}
+
+/* ----------------------------------------------------------------------- */
+#elif 1
+
+/* get some information from the host compiler for configure */
+
 #include <stdio.h>
 
 #if defined(_WIN32)
@@ -123,3 +293,6 @@ int main(int argc, char *argv[])
     }
     return 0;
 }
+
+/* ----------------------------------------------------------------------- */
+#endif
diff --git a/i386-gen.c b/i386-gen.c
index d2727980..96419901 100644
--- a/i386-gen.c
+++ b/i386-gen.c
@@ -81,6 +81,11 @@ enum {
 #define USING_GLOBALS
 #include "tcc.h"
 
+ST_DATA const char *target_machine_defs =
+    "__i386__\0"
+    "__i386\0"
+    ;
+
 /* define to 1/0 to [not] have EBX as 4th register */
 #define USE_EBX 0
 
diff --git a/include/stddef.h b/include/stddef.h
index bd2d5b2b..536ebee3 100644
--- a/include/stddef.h
+++ b/include/stddef.h
@@ -17,25 +17,11 @@ typedef union { long long __ll; long double __ld; } max_align_t;
 typedef signed char int8_t;
 typedef signed short int int16_t;
 typedef signed int int32_t;
-#if defined(__LP64__) \
-  && !defined(__APPLE__) \
-  && !defined(__OpenBSD__) \
-  && !(defined(__NetBSD__) && defined(__aarch64__))
-typedef signed long int int64_t;
-#else
-typedef signed long long int int64_t;
-#endif
+typedef signed __INT64_TYPE__ int64_t;
 typedef unsigned char uint8_t;
 typedef unsigned short int uint16_t;
 typedef unsigned int uint32_t;
-#if defined(__LP64__) \
-  && !defined(__APPLE__) \
-  && !defined(__OpenBSD__) \
-  && !(defined(__NetBSD__) && defined(__aarch64__))
-typedef unsigned long int uint64_t;
-#else
-typedef unsigned long long int uint64_t;
-#endif
+typedef unsigned __INT64_TYPE__ uint64_t;
 #endif
 
 #ifndef NULL
diff --git a/include/tccdefs.h b/include/tccdefs.h
index 99967895..5cac7564 100644
--- a/include/tccdefs.h
+++ b/include/tccdefs.h
@@ -1,27 +1,43 @@
 /*  tccdefs.h
- *
- *  By using native platfórm macros this file may be included at runtime
- *  just as is.
- *
- *  If converted to C-strings and included in tccpp.c, these are trahslated
- *  to tcc target macros accordingly.
- */
+
+    Nothing is defined before this file except target machine, target os
+    and the few things related to option settings in tccpp.c:tcc_predefs().
+
+    This file is either included at runtime as is, or converted and
+    included as C-strings at compile-time (depending on CONFIG_TCC_PREDEFS).
+
+    Note that line indent matters:
+
+    - in lines starting at column 1, platform macros are replaced by
+      corresponding TCC target compile-time macros.  See conftest.c for
+      the list of platform macros supported in lines starting at column 1.
+
+    - only lines indented >= 4 are actually included into the executable,
+      check tccdefs_.h.
+*/
 
 #if __SIZEOF_POINTER__ == 4
     /* 32bit systems. */
     #define __SIZE_TYPE__ unsigned int
     #define __PTRDIFF_TYPE__ int
     #define __ILP32__ 1
+    #define __INT64_TYPE__ long long
 #elif __SIZEOF_LONG__ == 4
     /* 64bit Windows. */
     #define __SIZE_TYPE__ unsigned long long
     #define __PTRDIFF_TYPE__ long long
     #define __LLP64__ 1
+    #define __INT64_TYPE__ long long
 #else
     /* Other 64bit systems. */
     #define __SIZE_TYPE__ unsigned long
     #define __PTRDIFF_TYPE__ long
     #define __LP64__ 1
+# if defined __linux__
+    #define __INT64_TYPE__ long
+# else /* APPLE, BSD */
+    #define __INT64_TYPE__ long long
+# endif
 #endif
     #define __SIZEOF_INT__ 4
     #define __INT_MAX__ 0x7fffffff
@@ -58,15 +74,10 @@
     #endif
 
 #if defined _WIN32
-    //#define _WIN32 1
-# if __SIZEOF_POINTER__ == 8
-    #define _WIN64 1
-# endif
     #define __declspec(x) __attribute__((x))
     #define __cdecl
 
 #elif defined __FreeBSD__
-    //#define __FreeBSD__ 12
     #define __GNUC__ 9
     #define __GNUC_MINOR__ 3
     #define __GNUC_PATCHLEVEL__ 0
@@ -78,27 +89,22 @@
 # endif
 
 #elif defined __FreeBSD_kernel__
-    //#define __FreeBSD_kernel__ 1
 
 #elif defined __NetBSD__
-    //#define __NetBSD__ 1
     #define __GNUC__ 4
     #define __GNUC_MINOR__ 1
     #define __GNUC_PATCHLEVEL__ 0
     #define _Pragma(x)
     #define __ELF__ 1
-    #if defined(__aarch64__) && defined(__TINYC__) && !defined(_LOCORE)
-         /* avoids usage of __asm which is not yet supported by tcc */
-         #define _LOCORE
-    #endif
+#if defined __aarch64__
+    #define _LOCORE /* avoids usage of __asm */
+#endif
 
 #elif defined __OpenBSD__
-    //#define __OpenBSD__ 1
     #define __GNUC__ 4
     #define _ANSI_LIBRARY 1
 
 #elif defined __APPLE__
-    //#define __APPLE__ 1
     /* emulate APPLE-GCC to make libc's headerfiles compile: */
     #define __GNUC__ 4   /* darwin emits warning on GCC<4 */
     #define __APPLE_CC__ 1 /* for <TargetConditionals.h> */
@@ -108,8 +114,8 @@
     #define _FORTIFY_SOURCE 0
 
 #else
-    //#define __linux__ 1
-    //#define __linux 1
+    /* Linux */
+
 #endif
 
 #if !defined _WIN32
diff --git a/riscv64-gen.c b/riscv64-gen.c
index 384d0ec7..bdf932fd 100644
--- a/riscv64-gen.c
+++ b/riscv64-gen.c
@@ -36,6 +36,17 @@
 #include "tcc.h"
 #include <assert.h>
 
+ST_DATA const char *target_machine_defs =
+    "__riscv\0"
+    "__riscv_xlen 64\0"
+    "__riscv_flen 64\0"
+    "__riscv_div\0"
+    "__riscv_mul\0"
+    "__riscv_fdiv\0"
+    "__riscv_fsqrt\0"
+    "__riscv_float_abi_double\0"
+    ;
+
 #define XLEN 8
 
 #define TREG_RA 17
diff --git a/tcc.h b/tcc.h
index f28b9d86..03362b00 100644
--- a/tcc.h
+++ b/tcc.h
@@ -211,6 +211,11 @@ extern long double strtold (const char *__nptr, char **__endptr);
 # define ELF_OBJ_ONLY /* create elf .o but native executables */
 #endif
 
+/* No ten-byte long doubles on window except in cross-compilers made by GCC */
+#if defined TCC_TARGET_PE || (defined _WIN32 && !defined __GNUC__)
+# define TCC_USING_DOUBLE_FOR_LDOUBLE 1
+#endif
+
 /* ------------ path configuration ------------ */
 
 #ifndef CONFIG_SYSROOT
@@ -1620,7 +1625,7 @@ ST_FUNC void relocate_plt(TCCState *s1);
 ST_FUNC void relocate(TCCState *s1, ElfW_Rel *rel, int type, unsigned char *ptr, addr_t addr, addr_t val);
 
 /* ------------ xxx-gen.c ------------ */
-
+ST_DATA const char *target_machine_defs;
 ST_DATA const int reg_classes[NB_REGS];
 
 ST_FUNC void gsym_addr(int t, int a);
diff --git a/tccgen.c b/tccgen.c
index 0c3de487..1c9eb834 100644
--- a/tccgen.c
+++ b/tccgen.c
@@ -160,7 +160,11 @@ static const struct {
     {   VT_BYTE | VT_DEFSIGN | VT_UNSIGNED, "unsigned char:t13=r13;0;255;" },
     {   VT_FLOAT, "float:t14=r1;4;0;" },
     {   VT_DOUBLE, "double:t15=r1;8;0;" },
+#ifdef TCC_USING_DOUBLE_FOR_LDOUBLE
+    {   VT_DOUBLE | VT_LONG, "long double:t16=r1;8;0;" },
+#else
     {   VT_LDOUBLE, "long double:t16=r1;16;0;" },
+#endif
     {   -1, "_Float32:t17=r1;4;0;" },
     {   -1, "_Float64:t18=r1;8;0;" },
     {   -1, "_Float128:t19=r1;16;0;" },
@@ -5061,7 +5065,7 @@ the_end:
     bt = t & (VT_BTYPE|VT_LONG);
     if (bt == VT_LONG)
         t |= LONG_SIZE == 8 ? VT_LLONG : VT_INT;
-#if defined TCC_TARGET_PE || (defined _WIN32 && defined _MSC_VER)
+#ifdef TCC_USING_DOUBLE_FOR_LDOUBLE
     if (bt == VT_LDOUBLE)
         t = (t & ~(VT_BTYPE|VT_LONG)) | (VT_DOUBLE|VT_LONG);
 #endif
diff --git a/tccpp.c b/tccpp.c
index 449035db..2aa2c583 100644
--- a/tccpp.c
+++ b/tccpp.c
@@ -1840,8 +1840,6 @@ ST_FUNC void preprocess(int is_bof)
 
         if (s1->include_stack_ptr >= s1->include_stack + INCLUDE_STACK_SIZE)
             tcc_error("#include recursion too deep");
-        /* push current file on stack */
-        *s1->include_stack_ptr++ = file;
         i = tok == TOK_INCLUDE_NEXT ? file->include_next_index + 1 : 0;
         n = 2 + s1->nb_include_paths + s1->nb_sysinclude_paths;
         for (; i < n; ++i) {
@@ -1884,7 +1882,8 @@ ST_FUNC void preprocess(int is_bof)
 
             if (tcc_open(s1, buf1) < 0)
                 continue;
-
+            /* push previous file on stack */
+            *s1->include_stack_ptr++ = file->prev;
             file->include_next_index = i;
 #ifdef INC_DEBUG
             printf("%s: including %s\n", file->prev->filename, file->filename);
@@ -1907,7 +1906,6 @@ ST_FUNC void preprocess(int is_bof)
         }
         tcc_error("include file '%s' not found", buf);
 include_done:
-        --s1->include_stack_ptr;
         break;
     case TOK_IFNDEF:
         c = 1;
@@ -3625,97 +3623,77 @@ ST_INLN void unget_tok(int last_tok)
     tok = last_tok;
 }
 
+/* ------------------------------------------------------------------------- */
+/* init preprocessor */
+
+static const char *target_os_defs =
+#ifdef TCC_TARGET_PE
+    "_WIN32\0"
+# if PTR_SIZE == 8
+    "_WIN64\0"
+# endif
+#else
+# if defined TCC_TARGET_MACHO
+    "__APPLE__\0"
+# elif TARGETOS_FreeBSD
+    "__FreeBSD__ 12\0"
+# elif TARGETOS_FreeBSD_kernel
+    "__FreeBSD_kernel__\0"
+# elif TARGETOS_NetBSD
+    "__NetBSD__\0"
+# elif TARGETOS_OpenBSD
+    "__OpenBSD__\0"
+# else
+    "__linux__\0"
+    "__linux\0"
+# endif
+    "__unix__\0"
+    "__unix\0"
+#endif
+    ;
+
+static void putdef(CString *cs, const char *p)
+{
+    cstr_printf(cs, "#define %s%s\n", p, &" 1"[!!strchr(p, ' ')*2]);
+}
+
 static void tcc_predefs(TCCState *s1, CString *cs, int is_asm)
 {
-    int a,b,c;
+    int a, b, c;
+    const char *defs[] = { target_machine_defs, target_os_defs, NULL };
+    const char *p;
 
     sscanf(TCC_VERSION, "%d.%d.%d", &a, &b, &c);
     cstr_printf(cs, "#define __TINYC__ %d\n", a*10000 + b*100 + c);
-    cstr_cat(cs,
-        /* target machine */
-#if defined TCC_TARGET_I386
-        "#define __i386__ 1\n"
-        "#define __i386 1\n"
-#elif defined TCC_TARGET_X86_64
-        "#define __x86_64__ 1\n"
-        "#define __amd64__ 1\n"
-#elif defined TCC_TARGET_ARM
-        "#define __ARM_ARCH_4__ 1\n"
-        "#define __arm_elf__ 1\n"
-        "#define __arm_elf 1\n"
-        "#define arm_elf 1\n"
-        "#define __arm__ 1\n"
-        "#define __arm 1\n"
-        "#define arm 1\n"
-        "#define __APCS_32__ 1\n"
-        "#define __ARMEL__ 1\n"
-# if defined TCC_ARM_EABI
-        "#define __ARM_EABI__ 1\n"
-# endif
-#elif defined TCC_TARGET_ARM64
-        "#define __aarch64__ 1\n"
-#elif defined TCC_TARGET_C67
-        "#define __C67__ 1\n"
-#elif defined TCC_TARGET_RISCV64
-        "#define __riscv 1\n"
-        "#define __riscv_xlen 64\n"
-        "#define __riscv_flen 64\n"
-        "#define __riscv_div 1\n"
-        "#define __riscv_mul 1\n"
-        "#define __riscv_fdiv 1\n"
-        "#define __riscv_fsqrt 1\n"
-        "#define __riscv_float_abi_double 1\n"
-#endif
-        , -1);
+    for (a = 0; defs[a]; ++a)
+        for (p = defs[a]; *p; p = strchr(p, 0) + 1)
+            putdef(cs, p);
 #ifdef TCC_TARGET_ARM
     if (s1->float_abi == ARM_HARD_FLOAT)
-      cstr_printf(cs, "#define __ARM_PCS_VFP 1\n");
+      putdef(cs, "__ARM_PCS_VFP");
 #endif
-    cstr_cat(cs,
-        /* target platform */
-#ifdef TCC_TARGET_PE
-        "#define _WIN32 1\n"
-#else
-        "#define __unix__ 1\n"
-        "#define __unix 1\n"
-# if defined TCC_TARGET_MACHO
-        "#define __APPLE__ 1\n"
-# elif TARGETOS_FreeBSD
-        "#define __FreeBSD__ 12\n"
-# elif TARGETOS_FreeBSD_kernel
-        "#define __FreeBSD_kernel__ 1\n"
-# elif TARGETOS_NetBSD
-        "#define __NetBSD__ 1\n"
-# elif TARGETOS_OpenBSD
-        "#define __OpenBSD__ 1\n"
-# else
-        "#define __linux__ 1\n"
-        "#define __linux 1\n"
-# endif
-#endif
-        , -1);
     if (is_asm)
-      cstr_printf(cs, "#define __ASSEMBLER__ 1\n");
+      putdef(cs, "__ASSEMBLER__");
     if (s1->output_type == TCC_OUTPUT_PREPROCESS)
-      cstr_printf(cs, "#define __TCC_PP__ 1\n");
+      putdef(cs, "__TCC_PP__");
     if (s1->output_type == TCC_OUTPUT_MEMORY)
-      cstr_printf(cs, "#define __TCC_RUN__ 1\n");
+      putdef(cs, "__TCC_RUN__");
     if (s1->char_is_unsigned)
-      cstr_printf(cs, "#define __CHAR_UNSIGNED__ 1\n");
+      putdef(cs, "__CHAR_UNSIGNED__");
     if (s1->optimize > 0)
-      cstr_printf(cs, "#define __OPTIMIZE__ 1\n");
+      putdef(cs, "__OPTIMIZE__");
     if (s1->option_pthread)
-      cstr_printf(cs, "#define _REENTRANT 1\n");
+      putdef(cs, "_REENTRANT");
     if (s1->leading_underscore)
-      cstr_printf(cs, "#define __leading_underscore 1\n");
+      putdef(cs, "__leading_underscore");
 #ifdef CONFIG_TCC_BCHECK
     if (s1->do_bounds_check)
-      cstr_printf(cs, "#define __BOUNDS_CHECKING_ON 1\n");
+      putdef(cs, "__BOUNDS_CHECKING_ON");
 #endif
     cstr_printf(cs, "#define __SIZEOF_POINTER__ %d\n", PTR_SIZE);
     cstr_printf(cs, "#define __SIZEOF_LONG__ %d\n", LONG_SIZE);
     if (!is_asm) {
-      cstr_printf(cs, "#define __STDC__ 1\n");
+      putdef(cs, "__STDC__");
       cstr_printf(cs, "#define __STDC_VERSION__ %dL\n", s1->cversion);
       cstr_cat(cs,
         /* load more predefs and __builtins */
diff --git a/tests/libtcc_test_mt.c b/tests/libtcc_test_mt.c
index b17e8de2..47d493d8 100644
--- a/tests/libtcc_test_mt.c
+++ b/tests/libtcc_test_mt.c
@@ -269,7 +269,7 @@ int main(int argc, char **argv)
     printf("\n (%u ms)\n", getclock_ms() - t);
 #endif
 #if 1
-    printf("running tcc.c in threads to run fib\n"), fflush(stdout);
+    printf("running tcc.c in threads to run fib\n "), fflush(stdout);
     t = getclock_ms();
     for (n = 0; n < M; ++n)
         create_thread(thread_test_complex, n);
diff --git a/tests/misc/c2str.c b/tests/misc/c2str.c
deleted file mode 100644
index 71f242bc..00000000
--- a/tests/misc/c2str.c
+++ /dev/null
@@ -1,158 +0,0 @@
-#include <stdio.h>
-#include <string.h>
-
-/* replace native host macros by compile-time versions */
-const char *platform_macros[] = {
-    "__i386__",             "TCC_TARGET_I386",
-    "__x86_64__",           "TCC_TARGET_X86_64",
-    "_WIN32",               "TCC_TARGET_PE",
-    "__arm__",              "TCC_TARGET_ARM",
-    "__ARM_EABI__",         "TCC_ARM_EABI",
-    "__aarch64__",          "TCC_TARGET_ARM64",
-    "__riscv",              "TCC_TARGET_RISCV64",
-    "__APPLE__",            "TCC_TARGET_MACHO",
-    "__FreeBSD__",          "TARGETOS_FreeBSD",
-    "__FreeBSD_kernel__",   "TARGETOS_FreeBSD_kernel",
-    "__OpenBSD__",          "TARGETOS_OpenBSD",
-    "__NetBSD__",           "TARGETOS_NetBSD",
-    "__linux__",            "TARGETOS_Linux",
-    "__SIZEOF_POINTER__",   "PTR_SIZE",
-    "__SIZEOF_LONG__",      "LONG_SIZE",
-    0
-};
-
-int isid(int c)
-{
-    return (c >= 'a' && c <= 'z')
-        || (c >= 'A' && c <= 'Z')
-        || (c >= '0' && c <= '9')
-        || c == '_';
-}
-
-int isspc(int c)
-{
-    return c == ' ' || c == '\t';
-}
-
-int main(int argc, char **argv)
-{
-    char l[1000], l2[1000], *p, *q, *p0;
-    FILE *fp, *op;
-    int c, e, f, cmt, cmt_n;
-    const char *r;
-
-    if (argc < 3)
-        return 1;
-
-    fp = fopen(argv[1], "rb");
-    op = fopen(argv[2], "wb");
-    if (!fp || !op) {
-        fprintf(stderr, "c2str: file error\n");
-        return 1;
-    }
-
-    cmt = cmt_n = 0;
-    for (;;) {
-        p = l;
-    append:
-        if (fgets(p, sizeof l - (p - l), fp)) {
-            p = strchr(p, 0);
-            while (p > l && p[-1] <= ' ')
-                --p;
-            *p = 0;
-        } else if (p == l)
-            break;
-
-        /* check for continuation */
-        if (p > l && p[-1] == '\\') {
-            p[-1] = ' ';
-            goto append;
-        }
-
-        p = l, q = l2, f = 0;
-        /* count & skip leading spaces */
-        while (*p && isspc(*p))
-            ++p, ++f;
-
-        /* handle comments */
-        if (p[0] == '/' && cmt == 0) {
-            if (p[1] == '*')
-                cmt = 2;
-            if (p[1] == '/')
-                cmt = 1;
-        }
-        if (cmt) {
-            fprintf(op, "%s", l);
-            if (++cmt_n == 1)
-                fprintf(op, " (converted, do not edit this file)");
-            fprintf(op, "\n");
-            if (cmt == 1)
-                cmt = 0;
-            if (cmt == 2) {
-                p = strchr(l, 0);
-                if (p >= l + 2 && p[-1] == '/' && p[-2] == '*')
-                    cmt = 0;
-            }
-            continue;
-        }
-
-        if (f < 4) {
-            /* less than 4 leading spaces : no quotes but replace macros
-               by compile-time versions */
-            do {
-                for (f = 0; (r = platform_macros[f]); f += 2) {
-                    c = strlen(r);
-                    e = 0;
-                    /*if (memcmp(p, "defined ", 8))
-                        e = 8;*/
-                    if (0 == memcmp(p + e, r, c)) {
-                        p += e + c;
-                        q = strchr(strcpy(q, platform_macros[f + 1]), 0);
-                        break;
-                    }
-
-                }
-                if (r)
-                    continue;
-            } while (!!(*q++ = *p++));
-            fprintf(op, "%s\n", l2);
-            continue;
-
-        } else {
-            /* output line as C string */
-            e = f = 0, p0 = p;
-            for (;;) {
-                c = *p++;
-
-                if (c == '/' && (p[0] == '/' || p[0] == '*'))
-                    c = 0; /* trailing comment detected */
-
-                if (isspc(c)) {
-                    /* remove spaces if possible */
-                    if (q == l2 || isspc(q[-1]))
-                        continue;
-                    /* keep space after macro identifier */
-                    if ((f >= 2 || e) && (!isid(q[-1]) || !isid(*p)))
-                        continue;
-                    if (f == 1)
-                        f = 2;
-                }
-                if (c == '(')
-                    ++e;
-                if (c == ')')
-                    --e, f += e == 0;
-                if (c == '\\' || c == '\"')
-                    *q++ = '\\';
-                *q++ = c;
-                if (c == 0)
-                    break;
-                p0 = p;
-            }
-            fprintf(op, "    \"%s\\n\"%s\n", l2, p0);
-        }
-    }
-
-    fclose(fp);
-    fclose(op);
-    return 0;
-}
diff --git a/win32/include/_mingw.h b/win32/include/_mingw.h
index 4ac2651d..3f227f22 100644
--- a/win32/include/_mingw.h
+++ b/win32/include/_mingw.h
@@ -80,7 +80,6 @@
 #define __stdcall __attribute__((__stdcall__))
 #define _X86_ 1
 #define _M_IX86 300 /* Visual Studio */
-#define WIN32 1
 #define _USE_32BIT_TIME_T
 #endif
 
@@ -160,5 +159,6 @@ typedef struct localeinfo_struct _locale_tstruct,*_locale_t;
 #define __MINGW_EXTENSION
 #define WINAPI_FAMILY_PARTITION(X) 1
 #define MINGW_HAS_SECURE_API
+#define WIN32 1
 
 #endif /* __MINGW_H */
diff --git a/win32/include/errno.h b/win32/include/errno.h
index c2df0158..574ffa9b 100644
--- a/win32/include/errno.h
+++ b/win32/include/errno.h
@@ -14,7 +14,7 @@ extern "C" {
 
 #ifndef _CRT_ERRNO_DEFINED
 #define _CRT_ERRNO_DEFINED
-  _CRTIMP extern int *__cdecl _errno(void);
+  _CRTIMP int *__cdecl _errno(void);
 #define errno (*_errno())
 
   errno_t __cdecl _set_errno(int _Value);
diff --git a/win32/include/math.h b/win32/include/math.h
index 745ed376..8e66407e 100644
--- a/win32/include/math.h
+++ b/win32/include/math.h
@@ -274,7 +274,7 @@ extern "C" {
   : __signbitl (x))
 */
 #define signbit(x) \
-  _Generic(x, float: __signbitf, double: __signbit, long double: signbitl)(x)
+  _Generic(x, float: __signbitf, double: __signbit, long double: __signbitl)(x)
 
   extern double __cdecl exp2(double);
   extern float __cdecl exp2f(float);
diff --git a/win32/include/stdlib.h b/win32/include/stdlib.h
index 96765b29..033c0fdf 100644
--- a/win32/include/stdlib.h
+++ b/win32/include/stdlib.h
@@ -136,7 +136,7 @@ extern "C" {
 
 #ifndef _CRT_ERRNO_DEFINED
 #define _CRT_ERRNO_DEFINED
-  _CRTIMP extern int *__cdecl _errno(void);
+  _CRTIMP int *__cdecl _errno(void);
 #define errno (*_errno())
   errno_t __cdecl _set_errno(int _Value);
   errno_t __cdecl _get_errno(int *_Value);
diff --git a/win32/include/tcc/tcc_libm.h b/win32/include/tcc/tcc_libm.h
index cb256fe1..58b502e5 100644
--- a/win32/include/tcc/tcc_libm.h
+++ b/win32/include/tcc/tcc_libm.h
@@ -467,7 +467,7 @@ __CRT_INLINE long double __cdecl hypotl(long double x, long double y) { return h
 __CRT_INLINE long double __cdecl logl(long double x) { return log(x); }
 __CRT_INLINE long double __cdecl logbl(long double x) { return logb(x); }
 __CRT_INLINE long double __cdecl log10l(long double x) { return log10(x); }
-__CRT_INLINE long double __cdecl modfl(long double x, long double* y) { return modf(x, y); }
+__CRT_INLINE long double __cdecl modfl(long double x, long double* y) { double y1 = *y; x = modf(x, &y1); *y = y1; return x; }
 __CRT_INLINE long double __cdecl powl(long double x, long double y) { return pow(x, y); }
 __CRT_INLINE long double __cdecl sinhl(long double x) { return sinh(x); }
 __CRT_INLINE long double __cdecl sinl(long double x) { return sin(x); }
diff --git a/x86_64-gen.c b/x86_64-gen.c
index 9f9bf2c3..222249d4 100644
--- a/x86_64-gen.c
+++ b/x86_64-gen.c
@@ -112,6 +112,11 @@ enum {
 #include "tcc.h"
 #include <assert.h>
 
+ST_DATA const char *target_machine_defs =
+    "__x86_64__\0"
+    "__amd64__\0"
+    ;
+
 ST_DATA const int reg_classes[NB_REGS] = {
     /* eax */ RC_INT | RC_RAX,
     /* ecx */ RC_INT | RC_RCX,