Fixed various php compilation problems:

- Modified php building for buggy old toolchains
php/php-src#12774
https://sourceware.org/bugzilla/show_bug.cgi?id=23169

- Patched php configure script for ubuntu-16 old gcc version 5
The check in php/build/php.m4 is not sufficient to guard for gcc 5 on ubuntu 16

Ticket: ENT-12140
Changelog: none.

deps-packaging/php/cfbuild-php.spec

@@ -34,7 +34,7 @@ fi
   --with-iconv \
   --with-zlib=%{prefix} \
   --with-libmbfl=%{prefix} \
-  --enable-mbstring \
+  --enable-mbstring=shared \
   --enable-sockets \
   --disable-mbregex \
   --without-fpm-user \

deps-packaging/php/debian/rules

@@ -12,6 +12,7 @@ build: build-stamp
 build-stamp:
 	dh_testdir
 
+	patch -p0 < $(CURDIR)/old-gcc-check-avx512-better.patch
 	./configure --prefix=$(PREFIX)/httpd/php \
 --with-config-file-scan-dir=$(PREFIX)/httpd/php/lib \
 --with-apxs2=$(PREFIX)/httpd/bin/apxs \
@@ -22,7 +23,7 @@ build-stamp:
 --with-iconv \
 --with-zlib=$(PREFIX) \
 --with-libmbfl=$(PREFIX) \
---enable-mbstring \
+--enable-mbstring=shared \
 --enable-sockets \
 --disable-mbregex \
 --without-fpm-user \

deps-packaging/php/old-gcc-check-avx512-better.patch

@@ -0,0 +1,21 @@
+--- configure.old
++++ configure
+@@ -18114,6 +18114,10 @@ printf %s "checking for avx512 supports in compiler... " >&6; }
+     #include <immintrin.h>
+       int main(void) {
+         __m512i mask = _mm512_set1_epi32(0x1);
++        __builtin_cpu_supports("avx512dq");
++        __builtin_cpu_supports("avx512cd");
++        __builtin_cpu_supports("avx512bw");
++        __builtin_cpu_supports("avx512vl");
+         char out[32];
+         _mm512_storeu_si512(out, _mm512_shuffle_epi8(mask, mask));
+         return 0;
+@@ -18152,6 +18156,7 @@ printf %s "checking for avx512 vbmi supports in compiler... " >&6; }
+
+     #include <immintrin.h>
+       int main(void) {
++        __builtin_cpu_supports("avx512vbmi");
+         __m512i mask = _mm512_set1_epi32(0x1);
+         char out[32];
+         _mm512_storeu_si512(out, _mm512_permutexvar_epi8(mask, mask));