[Buildroot] [git commit branch/2021.11.x] package/libiio: set PYTHON_EXECUTABLE

[Peter Korsgaard]

commit: https://git.buildroot.net/buildroot/commit/?id=2686b22bc5254163519974fc85f85f609ac0a363
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/2021.11.x

Set PYTHON_EXECUTABLE to avoid the following build failure when
BR2_PACKAGE_PYTHON is enabled but libiio finds python3 without
setuptools on host:

-- Found Python: /usr/bin/python3.5 (found version "3.5.3") found components: Interpreter
-- new
-- Python_EXECUTABLE /usr/bin/python3.5

[...]

Traceback (most recent call last):
  File "/home/buildroot/autobuild/instance-0/output-1/build/libiio-0.23/bindings/python/setup.py", line 15, in <module>
    from setuptools import setup
ImportError: No module named 'setuptools'

Fixes:
 - http://autobuild.buildroot.org/results/d80e56e4ad84c8e7f244cf6d1cb96c116e8eb734

Signed-off-by: Fabrice Fontaine <fontaine.fabrice at gmail.com>
Acked-by: Paul Cercueil <paul at crapouillou.net>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout at mind.be>
(cherry picked from commit f384de4f4ec646c28dab6c442dd6bb2f06628725)
Signed-off-by: Peter Korsgaard <peter at korsgaard.com>
---
 package/libiio/libiio.mk | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/package/libiio/libiio.mk b/package/libiio/libiio.mk
index f706298c22..38b2f83e6e 100644
--- a/package/libiio/libiio.mk
+++ b/package/libiio/libiio.mk
@@ -76,8 +76,10 @@ endif
 ifeq ($(BR2_PACKAGE_LIBIIO_BINDINGS_PYTHON),y)
 ifeq ($(BR2_PACKAGE_PYTHON),y)
 LIBIIO_DEPENDENCIES += host-python-setuptools python
+LIBIIO_CONF_OPTS += -DPYTHON_EXECUTABLE=$(HOST_DIR)/bin/python
 else ifeq ($(BR2_PACKAGE_PYTHON3),y)
 LIBIIO_DEPENDENCIES += host-python3-setuptools python3
+LIBIIO_CONF_OPTS += -DPYTHON_EXECUTABLE=$(HOST_DIR)/bin/python3
 endif
 LIBIIO_CONF_OPTS += -DPYTHON_BINDINGS=ON
 else