From 9e7e6a5a1e4a8785e237a9c94b533e0c6d9dab91 Mon Sep 17 00:00:00 2001
From: David Carlier <devnexen@gmail.com>
Date: Sat, 17 Feb 2024 21:38:21 +0000
Subject: [PATCH 2/2] 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
Upstream-Status: Backport [cc46a4e6b5a413bab3e264c1dcaaf7052f54fbc4]
---
 ext/intl/config.m4 | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/ext/intl/config.m4 b/ext/intl/config.m4
index 7285f75e06a..36cf76e2932 100644
--- a/ext/intl/config.m4
+++ b/ext/intl/config.m4
@@ -83,7 +83,16 @@ 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 $ICU_CXXFLAGS"
   if test "$ext_shared" = "no"; then
     PHP_ADD_SOURCES(PHP_EXT_DIR(intl), $PHP_INTL_CXX_SOURCES, $PHP_INTL_CXX_FLAGS)
-- 
2.46.2