fix a preprocessor for .S

Lets assume that in *.S files a preprocessor directive
    follow '#' char w/o spaces between. Otherwise there is
    too many problems with the content of the comments.

tcc.h

@@ -1149,6 +1149,7 @@ ST_DATA TokenSym **table_ident;
                                         returned at eof */
 #define PARSE_FLAG_ASM_COMMENTS 0x0008 /* '#' can be used for line comment */
 #define PARSE_FLAG_SPACES     0x0010 /* next() returns space tokens (for -E) */
+#define PARSE_FLAG_ASM_FILE 0x0020 /* we processing an asm file */
 
 ST_FUNC TokenSym *tok_alloc(const char *str, int len);
 ST_FUNC char *get_tok_str(int v, CValue *cv);