EomExifUtil: Fix build with newer GCC

Newer gcc may produce an error if they cannot
check the format arguments.

EomExifUtil: Fix build with older GCCs

Older GCCs don't support pragma diagnostic in functions.
Move the pragmas outside to fix the build with these compilers.

https://bugzilla.gnome.org/show_bug.cgi?id=780675

origin commits:
https://gitlab.gnome.org/GNOME/eog/commit/ca4c09a
https://gitlab.gnome.org/GNOME/eog/commit/d91cf5b

src/eom-exif-util.c

@@ -95,6 +95,12 @@ _calculate_wday_yday (struct tm *tm)
 	tm->tm_yday = tmp_tm.tm_yday;
 }
 
+/* Older GCCs don't support pragma diagnostic inside functions.
+ * Put these here to avoid problems with the strftime format strings
+ * without breaking the build for these older GCCs */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wformat-nonliteral"
+
 #ifdef HAVE_STRPTIME
 static gchar *
 eom_exif_util_format_date_with_strptime (const gchar *date, const gchar* format)
@@ -164,6 +170,8 @@ eom_exif_util_format_date_by_hand (const gchar *date, const gchar* format)
 }
 #endif /* HAVE_STRPTIME */
 
+#pragma GCC diagnostic pop
+
 /**
  * eom_exif_util_format_date:
  * @date: a date string following Exif specifications