scripts: add support for architecture dependent functions

This is necessary to keep architecture dependent code separate from
common code.
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: <20200923134758.19354-3-mhartmay@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

README.md

@@ -134,7 +134,8 @@ all unit tests.
 ## Directory structure
 
     .:                  configure script, top-level Makefile, and run_tests.sh
-    ./scripts:          helper scripts for building and running tests
+    ./scripts:          general architecture neutral helper scripts for building and running tests
+    ./scripts/<ARCH>:   architecture dependent helper scripts for building and running tests
     ./lib:              general architecture neutral services for the tests
     ./lib/<ARCH>:       architecture dependent services for the tests
     ./<ARCH>:           the sources of the tests and the created objects/images

scripts/common.bash

+source config.mak
 
 function for_each_unittest()
 {
@@ -52,3 +53,10 @@ function for_each_unittest()
 	fi
 	exec {fd}<&-
 }
+
+# The current file has to be the only file sourcing the arch helper
+# file
+ARCH_FUNC=scripts/${ARCH}/func.bash
+if [ -f "${ARCH_FUNC}" ]; then
+	source "${ARCH_FUNC}"
+fi