diff '--color=auto' -aurN a/ext/intl/config.m4 b/ext/intl/config.m4
--- a/ext/intl/config.m4	2024-07-17 18:54:08.645892664 -0400
+++ b/ext/intl/config.m4	2024-07-17 18:54:29.506419432 -0400
@@ -85,7 +85,16 @@
     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([$PKG_CONFIG icu-uc --atleast-version=74],[
+    AC_MSG_RESULT([yes])
+    PHP_CXX_COMPILE_STDCXX(17, mandatory, PHP_INTL_STDCXX)
+  ],[
+    AC_MSG_RESULT([no])
+    PHP_CXX_COMPILE_STDCXX(11, mandatory, PHP_INTL_STDCXX)
+  ])
+
   PHP_INTL_CXX_FLAGS="$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"