from:php image: allow apt install of php-embed

Makefile

@@ -65,6 +65,7 @@ Dockerfile.php7.3: unit/version
 			-e 's,@@UNITPACKAGES@@,$(MODULE_php7.3),g' \
 			-e 's,@@UNIT_VERSION@@,$(UNIT_VERSION),g' \
 			> Dockerfile.php7.3
+	patch Dockerfile.php7.3 patch-Dockerfile.php7.3
 
 build-%: Dockerfile.%
 	docker build -t unit:$(VERSION)-$* -f Dockerfile.$* .

patch-Dockerfile.php7.3

@@ -0,0 +1,27 @@
+diff --git a/pkg/docker/Dockerfile.tmpl b/pkg/docker/Dockerfile.tmpl
+index 18d6d34..5fa7ad6 100644
+--- a/pkg/docker/Dockerfile.tmpl
++++ b/pkg/docker/Dockerfile.tmpl
+@@ -4,6 +4,14 @@ LABEL maintainer="NGINX Docker Maintainers <docker-maint@nginx.com>"
+ 
+ ENV UNIT_VERSION          @@UNIT_VERSION@@
+ 
++# php-embed package is a dependency of unit-php
++RUN set -eux; \
++	{ \
++		echo 'Package: php-embed php-common php-composer-ca-bundle php-curl php-mbstring php7.3-curl php7.3-mbstring php7.3-common'; \
++		echo 'Pin: release n=buster'; \
++		echo 'Pin-Priority: 1000'; \
++	} > /etc/apt/preferences.d/00-debian-php-embed
++
+ RUN set -x \
+ 	&& apt-get update \
+ 	&& apt-get install --no-install-recommends --no-install-suggests -y gnupg1 apt-transport-https ca-certificates \
+@@ -74,6 +82,7 @@ RUN set -x \
+ 						$unitPackages \
+                         curl \
+ 	&& apt-get remove --purge --auto-remove -y apt-transport-https && rm -rf /var/lib/apt/lists/* /etc/apt/sources.list.d/unit.list \
++	&& ln -sf /usr/share/php/Embed /usr/local/lib/php/Embed
+ 	\
+ # if we have leftovers from building, let's purge them (including extra, unnecessary build deps)
+ 	&& if [ -n "$tempDir" ]; then \