Fixed bug #76153 Intl compilation fails with icu4c 61.1

Additionally, ICU >= 59.1 requires C++11, so add the flags. Some
refactoring is needed to comply with the latest recommended build
options, such as automatic icu namespace addition.

acinclude.m4

@@ -2248,6 +2248,9 @@ AC_DEFUN([PHP_SETUP_ICU],[
     ICU_LIBS=`$ICU_CONFIG --ldflags --ldflags-icuio`
     PHP_EVAL_INCLINE($ICU_INCS)
     PHP_EVAL_LIBLINE($ICU_LIBS, $1)
+
+    ICU_EXTRA_FLAGS=`$ICU_CONFIG --cxxflags`
+    ICU_EXTRA_FLAGS="$ICU_EXTRA_FLAGS -DU_USING_ICU_NAMESPACE=1"
   fi
 ])
 

ext/intl/config.m4

@@ -86,7 +86,7 @@ if test "$PHP_INTL" != "no"; then
     breakiterator/codepointiterator_methods.cpp \
     uchar/uchar.c \
     idn/idn.c \
-    $icu_spoof_src, $ext_shared,,$ICU_INCS -Wno-write-strings -D__STDC_LIMIT_MACROS -DZEND_ENABLE_STATIC_TSRMLS_CACHE=1,cxx)
+    $icu_spoof_src, $ext_shared,,$ICU_INCS -Wno-write-strings -D__STDC_LIMIT_MACROS -DZEND_ENABLE_STATIC_TSRMLS_CACHE=1 $ICU_EXTRA_FLAGS,cxx)
   PHP_ADD_BUILD_DIR($ext_builddir/collator)
   PHP_ADD_BUILD_DIR($ext_builddir/converter)
   PHP_ADD_BUILD_DIR($ext_builddir/common)

ext/intl/config.w32

@@ -130,7 +130,7 @@ if (PHP_INTL != "no") {
 			ADD_FLAG("LIBS_INTL", "iculx.lib");
 		}
 
-		ADD_FLAG("CFLAGS_INTL", "/EHsc");
+		ADD_FLAG("CFLAGS_INTL", "/EHsc /D U_USING_ICU_NAMESPACE=1");
 		AC_DEFINE("HAVE_INTL", 1, "Internationalization support enabled");
 	} else {
 		WARNING("intl not enabled; libraries and/or headers not found");