multi-server: fix clean targets, move framework clone to build/

- clean.test.multi-server removes build/tests/multi-server/
- distclean.test.multi-server also removes the cloned framework
- Framework now clones to build/freeradius-multi-server/ so clean
  doesn't force a re-clone on every test run
- Add comment explaining why abspath is needed

Author: arr2036

src/tests/multi-server/all.mk

@@ -21,14 +21,18 @@ top_srcdir	:= $(abspath ./)
 BUILD_DIR	:= ${top_srcdir}/build
 endif
 
+# abspath is needed because BUILD_DIR is relative ("build") when
+# included from the top-level makefile, but paths are passed to
+# external tools (config_builder.py, docker compose) which need
+# absolute paths.
 DIR    := $(abspath ${top_srcdir}/src/tests/multi-server)
 OUTPUT := $(abspath $(BUILD_DIR)/tests/multi-server)
 
 # FIXME: We should be using packaged versions of the multi-server test framework
 # instead of cloning from git.
 TEST_MULTI_SERVER_GIT_REPO   := https://github.com/InkbridgeNetworks/freeradius-multi-server.git
 TEST_MULTI_SERVER_GIT_BRANCH := main
-TEST_MULTI_SERVER_FRAMEWORK_DIR := $(OUTPUT)/freeradius-multi-server
+TEST_MULTI_SERVER_FRAMEWORK_DIR := $(abspath $(BUILD_DIR)/freeradius-multi-server)
 
 #
 #  Debug and verbosity settings
@@ -205,9 +209,16 @@ test.multi-server.ci: $(TEST_MULTI_SERVER_CI_TESTS)
 
 .PHONY: clean.test.multi-server
 clean.test.multi-server:
+	rm -rf $(OUTPUT)
 
+.PHONY: distclean.test.multi-server
+distclean.test.multi-server: clean.test.multi-server
+	rm -rf $(TEST_MULTI_SERVER_FRAMEWORK_DIR)
 
 .PHONY: clean
 clean: clean.test.multi-server
 
+.PHONY: distclean
+distclean: distclean.test.multi-server
+
 clean.test: clean.test.multi-server