From cc46a4e6b5a413bab3e264c1dcaaf7052f54fbc4 Mon Sep 17 00:00:00 2001
From: David Carlier <devnexen@gmail.com>
Date: Sat, 17 Feb 2024 21:38:21 +0000
Subject: [PATCH] ext/intl: level up c++ runtime std for icu 74 and onwards.

to align with what is required to build icu 74 itself.

Close GH-14002
---
 ext/intl/config.m4 | 11 ++++++++++-
 1 files changed, 10 insertions(+), 1 deletion(-)
 
diff --git a/ext/intl/config.m4 b/ext/intl/config.m4
index dd687bcd97de3..48f5147ca7bbf 100644
--- a/ext/intl/config.m4
+++ b/ext/intl/config.m4
@@ -80,7 +80,16 @@ if test "$PHP_INTL" != "no"; then
     breakiterator/codepointiterator_methods.cpp"
 
   PHP_REQUIRE_CXX()
-  PHP_CXX_COMPILE_STDCXX(11, mandatory, PHP_INTL_STDCXX)
+
+  AC_MSG_CHECKING([if intl requires -std=gnu++17])
+  AS_IF([test "$PKG_CONFIG icu-uc --atleast-version=74"],[
+    AC_MSG_RESULT([yes])
+    PHP_CXX_COMPILE_STDCXX(17, mandatory, PHP_INTL_STDCXX)
+  ],[
+    AC_MSG_RESULT([no])
+    PHP_CXX_COMPILE_STDCXX(11, mandatory, PHP_INTL_STDCXX)
+  ])
+
   PHP_INTL_CXX_FLAGS="$INTL_COMMON_FLAGS $PHP_INTL_STDCXX $ICU_CXXFLAGS"
   case $host_alias in
   *cygwin*) PHP_INTL_CXX_FLAGS="$PHP_INTL_CXX_FLAGS -D_POSIX_C_SOURCE=200809L"