Fixed building ffi on PHP 7.4

Dockerfiles/mods/Dockerfile-7.4

@@ -183,17 +183,8 @@ RUN set -eux \
 # -------------------- Installing PHP Extension: ffi --------------------
 RUN set -eux \
 	# Installation: Generic
-	# Type:         GIT extension
-	&& git clone https://github.com/dstogov/php-ffi /tmp/ffi \
-	&& cd /tmp/ffi \
-	# Custom:       Install command
-	&& phpize \
-&& ./configure --with-ffi \
-&& make -j$(getconf _NPROCESSORS_ONLN) \
-&& make install \
- \
-	# Enabling
-	&& docker-php-ext-enable ffi \
+	# Type:         Built-in extension
+	&& docker-php-ext-install -j$(getconf _NPROCESSORS_ONLN) ffi \
 	&& true