run_tests/mkstandalone: add arch_cmd hook

This allows us, for example, to auto generate a new test case based on
an existing test case.

Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Message-Id: <20200923134758.19354-4-mhartmay@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

scripts/common.bash

@@ -19,7 +19,7 @@ function for_each_unittest()
 	while read -r -u $fd line; do
 		if [[ "$line" =~ ^\[(.*)\]$ ]]; then
 			if [ -n "${testname}" ]; then
-				"$cmd" "$testname" "$groups" "$smp" "$kernel" "$opts" "$arch" "$check" "$accel" "$timeout"
+				$(arch_cmd) "$cmd" "$testname" "$groups" "$smp" "$kernel" "$opts" "$arch" "$check" "$accel" "$timeout"
 			fi
 			testname=${BASH_REMATCH[1]}
 			smp=1
@@ -49,11 +49,16 @@ function for_each_unittest()
 		fi
 	done
 	if [ -n "${testname}" ]; then
-		"$cmd" "$testname" "$groups" "$smp" "$kernel" "$opts" "$arch" "$check" "$accel" "$timeout"
+		$(arch_cmd) "$cmd" "$testname" "$groups" "$smp" "$kernel" "$opts" "$arch" "$check" "$accel" "$timeout"
 	fi
 	exec {fd}<&-
 }
 
+function arch_cmd()
+{
+	[ "${ARCH_CMD}" ] && echo "${ARCH_CMD}"
+}
+
 # The current file has to be the only file sourcing the arch helper
 # file
 ARCH_FUNC=scripts/${ARCH}/func.bash