add dabuild.conf support

dabuild.conf

+# docker-abuild (dabuild) configuration file
+# uncomment to enable (defaults and options are provided)
+# NOTE: these settings will override environment variables
+
+# Override hosts architecture for build container.
+# Options are: x86|x86_64|aarch64|armhf|armv7
+# DABUILD_ARCH=$(uname -m)
+
+# Arguments to Passed through to the container run command line.
+# DABUILD_ARGS=
+
+# Create and use Docker named volumes as caches for the running container,
+# persisting changes across invocations
+# DABUILD_CACHE=false
+
+# If set while DABUILD_CACHE=true then remove and recreate the volumes
+# acting as caches.
+# DABUILD_CLEAN=false
+
+# Output debug messages to stdout.
+# DABUILD_DEBUG=false
+
+# Sets the CLI tool to use to run the container.
+# Options are docker or podman.
+# DABUILD_DOCKER=docker
+
+# Do not remove intermediate containers if set to false. 
+# DABUILD_RM=true
+
+# Sets the Alpine version of the container in which the abuild invocation takes
+# place. Defaults to your aports current branch, either N.N-stable or edge
+# DABUILD_VERSION=

dabuild.in

@@ -10,6 +10,11 @@ die () {
   exit 1
 }
 
+# source the configuration if available
+if [ -f "/etc/dabuild.conf" ]; then
+	. /etc/dabuild.conf
+fi
+
 ## debug
 if [ "$DABUILD_DEBUG" = "true" ]; then
   set -x