Remove build deps after building yaml PHP ext

Author: macbre

Dockerfile

@@ -17,13 +17,11 @@ RUN /usr/bin/composer -v
 #
 FROM php:$PHP_VERSION-cli-alpine AS php
 RUN apk add \
-		autoconf \
 		bzip2-dev \
 		libsodium-dev \
 		libxml2-dev \
 		libxslt-dev \
-		linux-headers \
-		yaml-dev
+		linux-headers
 
 # fixes "sockets" compilation issues
 # sendrecvmsg.c:128:19: error: invalid application of 'sizeof' to incomplete type 'struct cmsgcred'
@@ -47,9 +45,10 @@ RUN docker-php-ext-install \
 
 # install yaml extensions from PECL
 # https://pecl.php.net/package/yaml/2.2.3
-RUN apk add gcc make g++ zlib-dev \
+RUN apk add --virtual build-deps autoconf gcc make g++ zlib-dev yaml-dev \
 	&& pecl channel-update pecl.php.net \
-	&& pecl install yaml-2.2.3 && docker-php-ext-enable yaml
+	&& pecl install yaml-2.2.3 && docker-php-ext-enable yaml \
+	&& apk del build-deps
 
 RUN which php; php -v; php -m; php -i | grep ini