Able to make only specified layer (#18)

Author: sabmeua

Makefile

@@ -1,11 +1,12 @@
 SHELL := /bin/bash
 php_versions = 72 73 74
+layer = *
 
 
 docker-images:
 	PWD=pwd
 	set -e; \
-	for dir in layers/*; do \
+	for dir in layers/${layer}; do \
 		for php_version in $(php_versions); do \
 			echo "###############################################"; \
 			echo "###############################################"; \
@@ -20,16 +21,16 @@ docker-images:
 # The PHP runtimes
 layers: docker-images
 	PWD=pwd
-	rm -rf export/layer-*.zip || true
+	rm -rf export/layer-${layer}.zip || true
 	mkdir export/tmp
 	set -e; \
-	for dir in layers/*; do \
+	for dir in layers/${layer}; do \
 		for php_version in $(php_versions); do \
 			echo "###############################################"; \
 			echo "###############################################"; \
 			echo "### Exporting $${dir} PHP$${php_version}"; \
 			echo "###"; \
-			cd ${PWD} ; rm -rf export/tmp/* || true ; cd export/tmp ; \
+			cd ${PWD} ; rm -rf export/tmp/${layer} || true ; cd export/tmp ; \
 			docker run --entrypoint "tar" bref/$${dir}-php-$${php_version} -ch -C /opt . | tar -x ; \
 			zip --quiet -X --recurse-paths ../`echo "$${dir}-php-$${php_version}" | sed -e "s/layers\//layer-/g"`.zip . ; \
 			echo ""; \