Enable opcache for php 5.5.0+

bin/install

@@ -15,7 +15,7 @@ install_php() {
 
   echo "Determining configuration options..."
   local source_path=$(get_download_file_path $install_type $version $tmp_download_dir)
-  local configure_options="$(construct_configure_options $install_path)"
+  local configure_options="$(construct_configure_options $install_path $version)"
   local make_flags="-j$ASDF_CONCURRENCY"
 
   local operating_system=$(uname -a)
@@ -109,8 +109,13 @@ install_composer() {
   $bin_path/php -r "unlink('composer-setup.php');"
 }
 
+version_greater_equal() {
+    printf '%s\n%s\n' "$2" "$1" | sort --check=quiet --version-sort
+}
+
 construct_configure_options() {
   local install_path=$1
+  local version=$2
 
   # many options included below are not applicable to newer PHP versions
   # including these will trigger a build warning, but will not b
@@ -153,6 +158,9 @@ construct_configure_options() {
     --with-zlib \
     --without-snmp"
 
+  # opcache is bundled with php 5.5.0 and later
+  version_greater_equal $version "5.5.0" && global_config="$global_config --enable-opcache"
+
   if [ "$PHP_CONFIGURE_OPTIONS" = "" ]; then
     local configure_options="$(os_based_configure_options) $global_config"
   else