[PATCH v9 04/26] win32: Simplify gmtime_r detection direct base on _POSIX_THREAD_SAFE_FUNCTIONS.

[Yonggang Luo]

First, this reduce the size of configure, configure are tending to removal in 
future,
and this didn't introduce any new feature or remove any exist feature.
Second, the current localtime_r detection are conflict with ncursesw detection 
in
mingw, when ncursesw detected, it will provide the following compile flags
pkg-config --cflags ncursesw
-D_XOPEN_SOURCE=600 -D_POSIX_C_SOURCE=199506L 
-IC:/CI-Tools/msys64/mingw64/include/ncursesw
And the compile flag _POSIX_C_SOURCE will always cause 
_POSIX_THREAD_SAFE_FUNCTIONS to
be defined, in new version of mingw, that's will cause localtime_r to be 
defined.
But the configure script didn't provide _POSIX_C_SOURCE macro, and that's will 
result
localtime_r not detected because localtime_r are defined in forceinline manner.

And finally cause conflict between QEMU defined localtime_r
struct tm *localtime_r(const time_t *timep, struct tm *result);
with mingw defined localtime_r

```
#if defined(_POSIX_C_SOURCE) && !defined(_POSIX_THREAD_SAFE_FUNCTIONS)
#define _POSIX_THREAD_SAFE_FUNCTIONS 200112L
#endif

#ifdef _POSIX_THREAD_SAFE_FUNCTIONS
__forceinline struct tm *__CRTDECL localtime_r(const time_t *_Time, struct tm 
*_Tm) {
  return localtime_s(_Tm, _Time) ? NULL : _Tm;
}
__forceinline struct tm *__CRTDECL gmtime_r(const time_t *_Time, struct tm 
*_Tm) {
  return gmtime_s(_Tm, _Time) ? NULL : _Tm;
}
__forceinline char *__CRTDECL ctime_r(const time_t *_Time, char *_Str) {
  return ctime_s(_Str, 0x7fffffff, _Time) ? NULL : _Str;
}
__forceinline char *__CRTDECL asctime_r(const struct tm *_Tm, char * _Str) {
  return asctime_s(_Str, 0x7fffffff, _Tm) ? NULL : _Str;
}
#endif
```

So I suggest remove this configure script, and restrict msys2/mingw version to 
easy to maintain.
And use _POSIX_THREAD_SAFE_FUNCTIONS to guard the localtime_r and counterpart 
functions

Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
---
 configure                 | 34 ----------------------------------
 include/sysemu/os-win32.h |  4 ++--
 util/oslib-win32.c        |  2 +-
 3 files changed, 3 insertions(+), 37 deletions(-)

diff --git a/configure b/configure
index dc4b7a2e55..bac48b5b49 100755
--- a/configure
+++ b/configure
@@ -2496,37 +2496,6 @@ if test "$vhost_net" = ""; then
   test "$vhost_kernel" = "yes" && vhost_net=yes
 fi
 
-##########################################
-# MinGW / Mingw-w64 localtime_r/gmtime_r check
-
-if test "$mingw32" = "yes"; then
-    # Some versions of MinGW / Mingw-w64 lack localtime_r
-    # and gmtime_r entirely.
-    #
-    # Some versions of Mingw-w64 define a macro for
-    # localtime_r/gmtime_r.
-    #
-    # Some versions of Mingw-w64 will define functions
-    # for localtime_r/gmtime_r, but only if you have
-    # _POSIX_THREAD_SAFE_FUNCTIONS defined. For fun
-    # though, unistd.h and pthread.h both define
-    # that for you.
-    #
-    # So this #undef localtime_r and #include <unistd.h>
-    # are not in fact redundant.
-cat > $TMPC << EOF
-#include <unistd.h>
-#include <time.h>
-#undef localtime_r
-int main(void) { localtime_r(NULL, NULL); return 0; }
-EOF
-    if compile_prog "" "" ; then
-        localtime_r="yes"
-    else
-        localtime_r="no"
-    fi
-fi
-
 ##########################################
 # pkg-config probe
 
@@ -7088,9 +7057,6 @@ if [ "$bsd" = "yes" ] ; then
   echo "CONFIG_BSD=y" >> $config_host_mak
 fi
 
-if test "$localtime_r" = "yes" ; then
-  echo "CONFIG_LOCALTIME_R=y" >> $config_host_mak
-fi
 if test "$qom_cast_debug" = "yes" ; then
   echo "CONFIG_QOM_CAST_DEBUG=y" >> $config_host_mak
 fi
diff --git a/include/sysemu/os-win32.h b/include/sysemu/os-win32.h
index d8978e28c0..3ac8a53bac 100644
--- a/include/sysemu/os-win32.h
+++ b/include/sysemu/os-win32.h
@@ -48,12 +48,12 @@
 #define siglongjmp(env, val) longjmp(env, val)
 
 /* Missing POSIX functions. Don't use MinGW-w64 macros. */
-#ifndef CONFIG_LOCALTIME_R
+#ifndef _POSIX_THREAD_SAFE_FUNCTIONS
 #undef gmtime_r
 struct tm *gmtime_r(const time_t *timep, struct tm *result);
 #undef localtime_r
 struct tm *localtime_r(const time_t *timep, struct tm *result);
-#endif /* CONFIG_LOCALTIME_R */
+#endif
 
 static inline void os_setup_signal_handling(void) {}
 static inline void os_daemonize(void) {}
diff --git a/util/oslib-win32.c b/util/oslib-win32.c
index c654dafd93..f2fa9a3549 100644
--- a/util/oslib-win32.c
+++ b/util/oslib-win32.c
@@ -106,7 +106,7 @@ void qemu_anon_ram_free(void *ptr, size_t size)
     }
 }
 
-#ifndef CONFIG_LOCALTIME_R
+#ifndef _POSIX_THREAD_SAFE_FUNCTIONS
 /* FIXME: add proper locking */
 struct tm *gmtime_r(const time_t *timep, struct tm *result)
 {
-- 
2.28.0.windows.1