[Qemu-block] [PATCH] tests: Fix Python 3 detection on older GNU make versions

[Eduardo Habkost]

The $(SHELLSTATUS) variable requires GNU make >= 4.2, but Travis
seems to provide an older version.  Change the existing rules to
use command output instead of exit code, to make it compatible
with older GNU make versions.

Signed-off-by: Eduardo Habkost <address@hidden>
---
I think that's the cause of the Travis failures.  I have
submitted a test job right now, at:
  https://travis-ci.org/ehabkost/qemu-hacks/jobs/451387962
Let's see if it fixes the issue.
---
 tests/Makefile.include | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/Makefile.include b/tests/Makefile.include
index d2e577eabb..074eece558 100644
--- a/tests/Makefile.include
+++ b/tests/Makefile.include
@@ -913,8 +913,8 @@ TESTS_RESULTS_DIR=$(BUILD_DIR)/tests/results
 # information please refer to "avocado --help".
 AVOCADO_SHOW=none
 
-$(shell $(PYTHON) -c 'import sys; assert sys.version_info >= (3,0)' >/dev/null 
2>&1)
-ifeq ($(.SHELLSTATUS),0)
+PYTHON3 = $(shell $(PYTHON) -c 'import sys; print(1 if sys.version_info >= (3, 
0) else 0)')
+ifeq ($(PYTHON3), 1)
 $(TESTS_VENV_DIR): $(TESTS_VENV_REQ)
        $(call quiet-command, \
             $(PYTHON) -m venv --system-site-packages $@, \
-- 
2.18.0.rc1.1.g3f1ff2140