Import of CCTZ from GitHub.

PiperOrigin-RevId: 550964088
Change-Id: I54e4bff1cf72442c34e1668dbe8af9337eb0aa46

absl/time/internal/cctz/BUILD.bazel

@@ -53,10 +53,11 @@ cc_library(
         "include/cctz/time_zone.h",
         "include/cctz/zone_info_source.h",
     ],
-    # OS X and iOS no longer use `linkopts = ["-framework CoreFoundation"]`
-    # as (1) bazel adds it automatically, and (2) it caused problems when
-    # cross-compiling for Android.
-    # See https://github.com/abseil/abseil-cpp/issues/326 for details.
+    linkopts = select({
+        "@platforms//os:osx": ["-Wl,-framework,CoreFoundation"],
+        "@platforms//os:ios": ["-Wl,-framework,CoreFoundation"],
+        "//conditions:default": [],
+    }),
     visibility = ["//visibility:public"],
     deps = [
         ":civil_time",

absl/time/internal/cctz/src/time_zone_format.cc

@@ -20,7 +20,7 @@
 
 #if defined(HAS_STRPTIME) && HAS_STRPTIME
 #if !defined(_XOPEN_SOURCE) && !defined(__OpenBSD__)
-#define _XOPEN_SOURCE  // Definedness suffices for strptime().
+#define _XOPEN_SOURCE 500  // Exposes definitions for SUSv2 (UNIX 98).
 #endif
 #endif