From: Ryan VanderMeulen <rvandermeulen@mozilla.com>
Date: Sat, 29 Aug 2026 11:23:36 -0400
Subject: Bug 2067508 - define O_NONBLOCK to 0 on platforms lacking it (mingw).

Cherry-pick of google/cctz@361e53992abb; abseil has not imported it yet.
---
 abseil-cpp/absl/time/internal/cctz/src/time_zone_info.cc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/abseil-cpp/absl/time/internal/cctz/src/time_zone_info.cc b/abseil-cpp/absl/time/internal/cctz/src/time_zone_info.cc
index 9abbde72d62..9d385b2772c 100644
--- a/abseil-cpp/absl/time/internal/cctz/src/time_zone_info.cc
+++ b/abseil-cpp/absl/time/internal/cctz/src/time_zone_info.cc
@@ -414,6 +414,9 @@ inline FilePtr FOpen(const char* path) {
   // absolute path) would block indefinitely or read unbounded data.
 #ifndef O_CLOEXEC
 #define O_CLOEXEC 0
+#endif
+#ifndef O_NONBLOCK
+#define O_NONBLOCK 0
 #endif
   const int fd = open(path, O_RDONLY | O_NONBLOCK | O_CLOEXEC);
   if (fd >= 0) {