all: Move the multi-configuration file reading routine to a common helper

Based on Emil's (xexaxo) feedback, we now have a common.sh file
that contains the implementation of the routine to read all config
files for kdump/pstore, and we use Makefile to join the files,
having the same implemention in all users.

Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>

common.sh

@@ -0,0 +1,21 @@
+
+#  This function has the purpose of loading the necessary external
+#  variables, in the form of one (or more) configuration file(s). If the
+#  procedure fails, we must abort - otherwise it'll fail in a later stage.
+load_kdump_config() {
+	HAVE_CFG_FILES=0
+	shopt -s nullglob
+	for cfg in "/usr/share/kdump.d"/*; do
+		if [ -f "$cfg" ]; then
+			. "$cfg"
+			HAVE_CFG_FILES=1
+		fi
+	done
+	shopt -u nullglob
+
+	if [ ${HAVE_CFG_FILES} -eq 0 ]; then
+		logger "kdump: no config files in /usr/share/kdump.d/ - aborting."
+		exit 1
+	fi
+}
+