makefiles/buildtest: add a buildtest-indocker

Add a 'buildtest-indocker' that forces executing 'buildtest' for loop
completely inside the container.
It prevents starting one container per compilation wich is slower but
it could hide errors where the host toolchain would be used

It is currently equivalent to `buildtest` but will change when the
`buidtest` handling will be move outside of `BUILD_IN_DOCKER`.

Display an error when executed without BUILD_IN_DOCKER=1.

Makefile.include

@@ -110,7 +110,7 @@ include $(RIOTMAKE)/info-nproc.inc.mk
 # List of boards variables
 include $(RIOTMAKE)/boards.inc.mk
 
-GLOBAL_GOALS += buildtest info-boards-supported info-boards-features-missing info-buildsizes info-buildsizes-diff
+GLOBAL_GOALS += buildtest buildtest-indocker info-boards-supported info-boards-features-missing info-buildsizes info-buildsizes-diff
 ifneq (, $(filter $(GLOBAL_GOALS), $(MAKECMDGOALS)))
   BOARD=none
 endif

makefiles/buildtests.inc.mk

@@ -1,4 +1,4 @@
-.PHONY: buildtest
+.PHONY: buildtest buildtest-indocker
 
 BUILDTEST_MAKE_REDIRECT ?= >/dev/null 2>&1
 
@@ -25,3 +25,17 @@ buildtest:
 	done ; \
 	$${RESULT}
 endif # BUILD_IN_DOCKER
+
+# Define 'buildtest-indocker' completely executed inside the container.
+# It prevents starting one container per compilation wich is slower but it
+# could hide errors where the host toolchain would be used
+ifeq ($(BUILD_IN_DOCKER),1)
+  buildtest-indocker: ..in-docker-container
+else
+ifeq ($(INSIDE_DOCKER),1)
+  buildtest-indocker: buildtest
+else
+  buildtest-indocker:
+	$(error $@ must be run with `BUILD_IN_DOCKER=1`)
+endif # INSIDE_DOCKER
+endif # BUILD_IN_DOCKER

makefiles/docker.inc.mk

@@ -6,6 +6,7 @@ export DOCKER_FLAGS ?= --rm
 export DOCKER_MAKECMDGOALS_POSSIBLE = \
   all \
   buildtest \
+  buildtest-indocker \
   scan-build \
   scan-build-analyze \
   tests-% \