Fix build with compilers that don't have __has_feature.
https://github.com/grpc/grpc/issues/29680
--- include/grpc/impl/codegen/port_platform.h.orig	2024-12-30 00:03:28.000000000 -0600
+++ include/grpc/impl/codegen/port_platform.h	2024-12-30 00:14:34.000000000 -0600
@@ -242,7 +242,9 @@
 #define GPR_CPU_POSIX 1
 #define GPR_POSIX_CRASH_HANDLER 1
 #endif
-#if !(defined(__has_feature) && __has_feature(cxx_thread_local))
+#ifndef __has_feature
+#define GPR_PTHREAD_TLS 1
+#elif !__has_feature(cxx_thread_local)
 #define GPR_PTHREAD_TLS 1
 #endif
 #define GPR_APPLE 1