Set secure SHELL options before RUN

Docker only evaluates the exit code of the last operation after the pipe
in a RUN statement to determine success. Specifying 'pipefail' will cause
the build to fail due to an error at any stage of a RUN command with
pipes.

Setting the -e option instructs bash to immediately exit if any command
in a RUN statement has a non-zero exit status.

Setting the -u option triggers an error if a variable is referenced that
has not been previously defined.

Setting runDeps using a list passed to 'apk info --installed' returns a
non zero exit status if one of the packages listed is not installed.
Added '|| true' to force an exit status of 0.

1.1.21.2/Dockerfile

@@ -3,10 +3,11 @@ FROM alpine:3.19.1
 ENV GEARMAND_VERSION 1.1.21
 ENV GEARMAND_SHA1 472d2a0019e69edefcd0c1ff57e9352982e6d3f5
 
+SHELL ["/bin/sh", "-euxo", "pipefail", "-c"]
+
 RUN addgroup -S gearman && adduser -G gearman -S -D -H -s /bin/false -g "Gearman Server" gearman
 
-RUN set -x \
-	&& apk add --no-cache --virtual .build-deps \
+RUN apk add --no-cache --virtual .build-deps \
 		wget \
 		tar \
 		ca-certificates \
@@ -44,7 +45,7 @@ RUN set -x \
 		scanelf --needed --nobanner --recursive /usr/local \
 			| awk '{ gsub(/,/, "\nso:", $2); print "so:" $2 }' \
 			| sort -u \
-			| xargs -r apk info --installed \
+			| xargs -r apk info --installed || true \
 			| sort -u \
 	)" \
 	&& apk add --virtual .gearmand-rundeps $runDeps \