Replace obsolete macro AC_TRY_COMPILE with AC_COMPILE_IFELSE

Autoconf made several macros obsolete in several versions behind
including the AC_TRY_COMPILE which should be replaced with current
AC_COMPILE_IFELSE instead.

config.m4

@@ -260,18 +260,13 @@ if test "$PHP_MEMCACHED" != "no"; then
     dnl # Always check if libmemcached was built with SASL support,
     dnl # because it will require sasl.h even if not used here.
     AC_CACHE_CHECK([for libmemcached sasl.h requirement], ac_cv_memc_sasl_support, [
-      AC_TRY_COMPILE(
-        [ #include <libmemcached/memcached.h> ],
-        [
+      AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <libmemcached/memcached.h>]], [[
         #if LIBMEMCACHED_WITH_SASL_SUPPORT
           /* yes */
         #else
         #  error "no sasl support"
         #endif
-        ],
-        [ ac_cv_memc_sasl_support="yes" ],
-        [ ac_cv_memc_sasl_support="no" ]
-      )
+        ]])],[ac_cv_memc_sasl_support="yes"],[ac_cv_memc_sasl_support="no"])
     ])
 
     if test "$ac_cv_memc_sasl_support" = "yes"; then
@@ -360,14 +355,9 @@ if test "$PHP_MEMCACHED" != "no"; then
       AC_MSG_RESULT([enabled])
 
       AC_CACHE_CHECK([whether libmemcachedprotocol is usable], ac_cv_have_libmemcachedprotocol, [
-        AC_TRY_COMPILE(
-          [ #include <libmemcachedprotocol-0.0/handler.h> ],
-          [ memcached_binary_protocol_callback_st s_test_impl;
+        AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <libmemcachedprotocol-0.0/handler.h>]], [[memcached_binary_protocol_callback_st s_test_impl;
             s_test_impl.interface.v1.delete_object = 0;
-          ],
-          [ ac_cv_have_libmemcachedprotocol="yes" ],
-          [ ac_cv_have_libmemcachedprotocol="no" ]
-        )
+          ]])],[ac_cv_have_libmemcachedprotocol="yes"],[ac_cv_have_libmemcachedprotocol="no"])
       ])
 
       if test "$ac_cv_have_libmemcachedprotocol" != "yes"; then