Bug#37611924 Abseil broken on FreeBSD

Build of Abseil is broken on FreeBSD.
Apply upstream fix.

Change-Id: I421ef6245aae8cafcefdbe7a4c8179e7c855a3de
(cherry picked from commit 640a9b8efd931ee7f5a26553e470ea82079746b9)

Author: Tor Didriksen

extra/abseil/abseil-cpp-20230802.1/absl/time/internal/cctz/src/time_zone_format.cc

@@ -19,7 +19,7 @@
 #endif
 
 #if defined(HAS_STRPTIME) && HAS_STRPTIME
-#if !defined(_XOPEN_SOURCE) && !defined(__OpenBSD__)
+#if !defined(_XOPEN_SOURCE) && !defined(__FreeBSD__) && !defined(__OpenBSD__)
 #define _XOPEN_SOURCE 500  // Exposes definitions for SUSv2 (UNIX 98).
 #endif
 #endif