Improve Docker build process, remove --disable-segfault-error (#5552)

* Improve Docker build process: remove  --disable-segfault-error
* add Dockerfile as a Makefile dependency, so image gets rebuilt when Dockerfile changes

Author: jordikroon

.docker/Dockerfile

@@ -18,5 +18,11 @@ RUN echo 'memory_limit = 512M' >> /usr/local/etc/php/conf.d/local.ini
 
 ENV FORMAT=xhtml
 
-CMD php doc-base/configure.php --disable-segfault-error && \
-    php phd/render.php --docbook doc-base/.manual.xml --output=/var/www/en/output --package PHP --format ${FORMAT}
+CMD ["sh", "-c", "\
+php doc-base/configure.php && \
+exec php phd/render.php \
+  --docbook doc-base/.manual.xml \
+  --output=/var/www/en/output \
+  --package PHP \
+  --format ${FORMAT}\
+"]

Makefile

@@ -27,8 +27,8 @@ php: .docker/built
 
 build: .docker/built
 
-.docker/built:
-	docker build\
-		--build-arg UID=${CURRENT_UID} --build-arg GID=${CURRENT_GID}\
+.docker/built: .docker/Dockerfile
+	docker build \
+		--build-arg UID=${CURRENT_UID} --build-arg GID=${CURRENT_GID} \
 		.docker -t php/doc-en
 	touch .docker/built