include timegm fallback

include/compat/limits.h

@@ -3,9 +3,6 @@
  * limits.h compatibility shim
  */
 
-#ifndef LIBCRYPTOCOMPAT_LIMITS_H
-#define LIBCRYPTOCOMPAT_LIMITS_H
-
 #ifdef _MSC_VER
 #if _MSC_VER >= 1900
 #include <../ucrt/limits.h>
@@ -22,5 +19,3 @@
 #define PATH_MAX MAXPATHLEN
 #endif
 #endif
-
-#endif

include/compat/time.h

@@ -14,6 +14,10 @@
 #include_next <time.h>
 #endif
 
-#ifdef _WIN32
+#ifndef HAVE_TIMEGM
+#ifdef  HAVE__MKGMTIME
 #define timegm(tm) _mkgmtime(tm)
+#else
+time_t timegm(struct tm *tm);
+#endif
 #endif