[PATCH] makefile: Fix recursive makes

[Ilias Apalodimas]

Since the Kbuild bump to 5.1 and specifically
commit af1a9935708a ("kbuild: make -r/-R effective in top Makefile for old Make versions")
the recursion rules have changed.

'make O=/output/dir/' as well as './test/py/test.py --bd sandbox --build'
is working fine but anything that recursively called the makefile was
failing e.g 'make tests', 'make qcheck' etc, which calls a bash script
that ends up calling the makefile again.

The reason is that the internal 'sub_make_done' variable of the makefile was set
after the first pass and the output dir was never evaluated properly.
Reset the variable value if we are executing any of these tests.

Fixes: commit af1a9935708a ("kbuild: make -r/-R effective in top Makefile for old Make versions")
Reported-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
---
 Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Makefile b/Makefile
index 2402f9313d8b..8cddee3c5a96 100644
--- a/Makefile
+++ b/Makefile
@@ -2666,6 +2666,10 @@ help:
 	@echo  'Execute "make" or "make all" to build all targets marked with [*] '
 	@echo  'For further info see the ./README file'
 
+ifneq ($(filter tests pcheck qcheck tcheck,$(MAKECMDGOALS)),)
+export sub_make_done := 0
+endif
+
 tests check:
 	$(srctree)/test/run
 
-- 
2.43.0