tcc -E -P10 : output all numbers as decimals

This may be used to preprocess Fabrice Bellards initial revision
in this repository to demonstrate its capability to compile and
run itself (on i386 32-bit linux or windows).

Initial revision: 27f6e16bae

Also needed:
* an empty stdio.h
* a wrapper named tc.c with

  void expr(void);
  void decl(int);
  void next(void);
  #include "tcc.c"

* an hello.c such as

  int main()
  {
      printf("Hello World\n");
      return 0;
  }

All files with unix LF only lines.  Then ...

* preprocess the source
  $ tcc -E -P10 -I. tcc.c -o tc1.c
* compile the compiler
  $ tcc -w -I. tc.c -o tc -ldl
* run it to compile and
   run itself to compile and
    run itself to compile and
     run itself to compile and
      run hello.c
$ ./tc tc1.c tc1.c tc1.c hello.c

--> Hello World!

------------------------------------------------------
* On i386 windows this may be added to the tc.c wrapper

  #ifdef _WIN32
  #include <windows.h>
  void *dlsym(int x, const char *func)
  {
      if (0 == strcmp(func, "dlsym"))
          return &dlsym;
      return GetProcAddress(LoadLibrary("msvcrt"), func);
  }
  #endif

tccpp.c

@@ -3711,6 +3711,12 @@ ST_FUNC int tcc_preprocess(TCCState *s1)
                 ;
     define_start = define_stack;
 
+    /* Credits to Fabrice Bellard's initial revision to demonstrate its
+       capability to compile and run itself, provided all numbers are
+       given as decimals. tcc -E -P10 will do. */
+    if (s1->Pflag == 1 + 10)
+        parse_flags |= PARSE_FLAG_TOK_NUM, s1->Pflag = 1;
+
 #ifdef PP_BENCH
     /* for PP benchmarks */
     do next(); while (tok != TOK_EOF); return 0;