Check for non standard timegm, and replace it if not available.

configure.ac

@@ -98,6 +98,11 @@ AC_CHECK_MEMBER([struct tm.tm_gmtoff],
 	,
 	[#include <time.h>])
 
+AC_CHECK_DECL([timegm], 
+	[AC_DEFINE(HAVE_TIMEGM, 1, [Define this if timegm function is available])],
+	,
+	[#include <time.h>])
+
 THREAD_LIBS=-lpthread
 AC_SUBST(THREAD_LIBS)
 

libisofs/util.c

@@ -1058,6 +1058,26 @@ void iso_datetime_17(unsigned char *buf, time_t t, int always_gmt)
 
 }
 
+#ifndef HAVE_TIMEGM
+static
+time_t timegm(struct tm *tm)
+{
+    time_t ret;
+    char *tz;
+
+    tz = getenv("TZ");
+    setenv("TZ", "", 1);
+    tzset();
+    ret = mktime(tm);
+    if (tz)
+        setenv("TZ", tz, 1);
+    else
+        unsetenv("TZ");
+    tzset();
+    return ret;
+}
+#endif
+
 time_t iso_datetime_read_7(const uint8_t *buf)
 {
     struct tm tm;