diff --git a/include/stdarg.h b/include/stdarg.h
index 00c5585b..080143da 100644
--- a/include/stdarg.h
+++ b/include/stdarg.h
@@ -4,22 +4,10 @@
 #ifdef __x86_64__
 #ifndef _WIN64
 
-//This should be in sync with the declaration on our lib/libtcc1.c
-/* GCC compatible definition of va_list. */
-typedef struct {
-    unsigned int gp_offset;
-    unsigned int fp_offset;
-    union {
-        unsigned int overflow_offset;
-        char *overflow_arg_area;
-    };
-    char *reg_save_area;
-} __va_list_struct;
+typedef __builtin_va_list va_list;
 
-typedef __va_list_struct va_list[1];
-
-void __va_start(__va_list_struct *ap, void *fp);
-void *__va_arg(__va_list_struct *ap, int arg_type, int size, int align);
+void __va_start(va_list ap, void *fp);
+void *__va_arg(va_list ap, int arg_type, int size, int align);
 
 #define va_start(ap, last) __va_start(ap, __builtin_frame_address(0))
 #define va_arg(ap, type)                                                \
@@ -27,9 +15,6 @@ void *__va_arg(__va_list_struct *ap, int arg_type, int size, int align);
 #define va_copy(dest, src) (*(dest) = *(src))
 #define va_end(ap) ((void)0)
 
-/* avoid conflicting definition for va_list on Macs. */
-#define _VA_LIST_T
-
 #else /* _WIN64 */
 typedef char *va_list;
 #define va_start(ap,last) __builtin_va_start(ap,last)
diff --git a/lib/Makefile b/lib/Makefile
index 9d74dc35..7a5bb876 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -36,10 +36,6 @@ else
  DSO_O = dsohandle.o
 endif
 
-ifdef CONFIG_OSX
- XFLAGS += -D_ANSI_SOURCE
-endif
-
 I386_O = libtcc1.o alloca86.o alloca86-bt.o $(BT_O)
 X86_64_O = libtcc1.o alloca86_64.o alloca86_64-bt.o $(BT_O)
 ARM_O = libtcc1.o armeabi.o alloca-arm.o armflush.o $(BT_O)
diff --git a/lib/bt-log.c b/lib/bt-log.c
index 73e0067f..94010b2f 100644
--- a/lib/bt-log.c
+++ b/lib/bt-log.c
@@ -3,6 +3,7 @@
 
 #include <stdio.h>
 #include <string.h>
+#include <stdarg.h>
 
 int (*__rt_error)(void*, void*, const char *, va_list);
 
diff --git a/lib/va_list.c b/lib/va_list.c
index dc2e62a5..6be9fa19 100644
--- a/lib/va_list.c
+++ b/lib/va_list.c
@@ -2,14 +2,16 @@
 
 #if defined __x86_64__
 
+#include "stdarg.h"
+
 /* Avoid include files, they may not be available when cross compiling */
 extern void *memset(void *s, int c, __SIZE_TYPE__ n);
 extern void abort(void);
 
 /* This should be in sync with our include/stdarg.h */
-enum __va_arg_type {
-    __va_gen_reg, __va_float_reg, __va_stack
-};
+#define __VA_GEN_REG    0
+#define __VA_FLOAT_REG  1
+#define __VA_STACK      2
 
 /* GCC compatible definition of va_list. */
 typedef struct {
@@ -22,43 +24,45 @@ typedef struct {
     char *reg_save_area;
 } __va_list_struct;
 
-void __va_start(__va_list_struct *ap, void *fp)
+void __va_start(va_list ap, void *fp)
 {
-    memset(ap, 0, sizeof(__va_list_struct));
-    *ap = *(__va_list_struct *)((char *)fp - 16);
-    ap->overflow_arg_area = (char *)fp + ap->overflow_offset;
-    ap->reg_save_area = (char *)fp - 176 - 16;
+    __va_list_struct * _ap = (__va_list_struct*) ap;
+    memset(_ap, 0, sizeof(__va_list_struct));
+    *_ap = *(__va_list_struct *)((char *)fp - 16);
+    _ap->overflow_arg_area = (char *)fp + _ap->overflow_offset;
+    _ap->reg_save_area = (char *)fp - 176 - 16;
 }
 
-void *__va_arg(__va_list_struct *ap,
-               enum __va_arg_type arg_type,
+void *__va_arg(va_list ap,
+               int arg_type,
                int size, int align)
 {
+    __va_list_struct * _ap = (__va_list_struct*) ap;
     size = (size + 7) & ~7;
     align = (align + 7) & ~7;
     switch (arg_type) {
-    case __va_gen_reg:
-        if (ap->gp_offset + size <= 48) {
-            ap->gp_offset += size;
-            return ap->reg_save_area + ap->gp_offset - size;
+    case __VA_GEN_REG:
+        if (_ap->gp_offset + size <= 48) {
+            _ap->gp_offset += size;
+            return _ap->reg_save_area + _ap->gp_offset - size;
         }
         goto use_overflow_area;
 
-    case __va_float_reg:
-        if (ap->fp_offset < 128 + 48) {
-            ap->fp_offset += 16;
-            return ap->reg_save_area + ap->fp_offset - 16;
+    case __VA_FLOAT_REG:
+        if (_ap->fp_offset < 128 + 48) {
+            _ap->fp_offset += 16;
+            return _ap->reg_save_area + _ap->fp_offset - 16;
         }
         size = 8;
         goto use_overflow_area;
 
-    case __va_stack:
+    case __VA_STACK:
     use_overflow_area:
-        ap->overflow_arg_area += size;
-        ap->overflow_arg_area = (char*)((long long)(ap->overflow_arg_area + align - 1) & -align);
-        return ap->overflow_arg_area - size;
+        _ap->overflow_arg_area += size;
+        _ap->overflow_arg_area = (char*)((long long)(_ap->overflow_arg_area + align - 1) & -align);
+        return _ap->overflow_arg_area - size;
 
-    default: /* should never happen */
+    default: /* should never h_appen */
         abort();
         return 0;
     }
diff --git a/libtcc.c b/libtcc.c
index fdbe2e7f..61fafe46 100644
--- a/libtcc.c
+++ b/libtcc.c
@@ -927,6 +927,16 @@ LIBTCCAPI TCCState *tcc_new(void)
     /* Some GCC builtins that are simple to express as macros.  */
     tcc_define_symbol(s, "__builtin_extract_return_addr(x)", "x");
 #endif /* ndef TCC_TARGET_PE */
+#ifdef TCC_TARGET_MACHO
+	/* emulate APPLE-GCC to make libc's headerfiles compile: */
+	tcc_define_symbol(s, "__APPLE__", "1");
+    tcc_define_symbol(s, "__GNUC__", "4");   /* darwin emits warning on GCC<4 */
+    
+    /* avoids usage of GCC/clang specific builtins in libc-headerfiles: */
+    tcc_define_symbol(s, "__FINITE_MATH_ONLY__", "1");
+    tcc_define_symbol(s, "_FORTIFY_SOURCE", "0");
+#endif /* ndef TCC_TARGET_MACHO */
+    tcc_define_symbol(s, "__builtin_va_list", "void *");
     return s;
 }