preprocess: "assign PARSE_FLAG_ASM_COMMENTS only for asm files"

    resolve a problem with the following test.c program, tcc -E test.c

    #ifdef	_XOPEN_SOURCE
    # define __USE_XOPEN	1
    # if (_XOPEN_SOURCE - 0) >= 500
    #  define __USE_XOPEN_EXTENDED	1
    #  define __USE_UNIX98	1
    #  undef _LARGEFILE_SOURCE
    #  define _LARGEFILE_SOURCE	1
    #  if (_XOPEN_SOURCE - 0) >= 600
    #   define __USE_XOPEN2K	1
    #   undef __USE_ISOC99
    #   define __USE_ISOC99		1
    #  endif
    # else
    #  ifdef _XOPEN_SOURCE_EXTENDED
    #   define __USE_XOPEN_EXTENDED	1
    #  endif
    # endif
    #endif

    int main() {}

    // # 17 "aaa.c"
    // aaa.c:17: error: #endif without matching #if

2 files changed, 3 insertions, 4 deletions

diff --git a/libtcc.c b/libtcc.c
index 90dd185..abef9c8 100644
--- a/libtcc.c
+++ b/libtcc.c
@@ -1166,7 +1166,7 @@ ST_FUNC int tcc_add_file_internal(TCCState *s1, const char *filename, int flags,
     /* if .S file, define __ASSEMBLER__ like gcc does */
     if ((filetype == TCC_FILETYPE_ASM) || (filetype == TCC_FILETYPE_ASM_PP)) {
         tcc_define_symbol(s1, "__ASSEMBLER__", NULL);
-        parse_flags = PARSE_FLAG_ASM_FILE;
+        parse_flags = PARSE_FLAG_ASM_FILE | PARSE_FLAG_ASM_COMMENTS;
     }
 #endif
 
diff --git a/tccpp.c b/tccpp.c
index 05e7c1f..de3f8ae 100644
--- a/tccpp.c
+++ b/tccpp.c
@@ -3290,9 +3290,8 @@ ST_FUNC int tcc_preprocess(TCCState *s1)
     preprocess_init(s1);
     ch = file->buf_ptr[0];
     tok_flags = TOK_FLAG_BOL | TOK_FLAG_BOF;
-    parse_flags = (parse_flags & PARSE_FLAG_ASM_FILE);
-    parse_flags |= PARSE_FLAG_ASM_COMMENTS | PARSE_FLAG_PREPROCESS |
-        PARSE_FLAG_LINEFEED | PARSE_FLAG_SPACES;
+    parse_flags &= (PARSE_FLAG_ASM_FILE | PARSE_FLAG_ASM_COMMENTS);
+    parse_flags |= PARSE_FLAG_PREPROCESS | PARSE_FLAG_LINEFEED | PARSE_FLAG_SPACES;
     token_seen = 0;
     file->line_ref = 0;
     file_ref = NULL;