[Buildroot] [git commit branch/next] package/uhd: fix python module detection

[Thomas Petazzoni]

commit: https://git.buildroot.net/buildroot/commit/?id=8736da7cbae5852946f4e14d3952f527d1e835c4
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/next

$(HOST_DIR)/bin/python symlink is only created when
BR2_PACKAGE_PYTHON3 is set.

When only host-python3 is used this symlink is not present and build fails
with:
-- Python checking for Python version 2.7 or greater
-- Python checking for Python version 2.7 or greater - unknown error
--
-- Python checking for Mako templates 0.4.2 or greater
-- Python checking for Mako templates 0.4.2 or greater - unknown error
--
-- Python checking for requests 2.0 or greater
-- Python checking for requests 2.0 or greater - unknown error
--
-- Python checking for numpy 1.7 or greater
-- Python checking for numpy 1.7 or greater - unknown error
--
-- Configuring LibUHD support...
--   Dependency Boost_FOUND = TRUE
--   Dependency HAVE_PYTHON_PLAT_MIN_VERSION = FALSE
--   Dependency HAVE_PYTHON_MODULE_MAKO = FALSE

This patch set explicitly PYTHON_EXECUTABLE to $(HOST_DIR)/bin/python3

This is a fallout from e9df5b0fc3f6e8bb36deedefb392bbc968116ee7, which
changed uhd to always use host-python3.

Fixes:
- http://autobuild.buildroot.net/results/35c0b9597c75dade241a3b3786fae30551c48008
- http://autobuild.buildroot.net/results/89069102bf8785ce8a9ec3b4c6fa32749c2e3586

Signed-off-by: Gwenhael Goavec-Merou <gwenhael.goavec-merou at trabucayre.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
---
 package/uhd/uhd.mk | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/package/uhd/uhd.mk b/package/uhd/uhd.mk
index 5da1697925..e8f197f9dd 100644
--- a/package/uhd/uhd.mk
+++ b/package/uhd/uhd.mk
@@ -19,7 +19,7 @@ UHD_DEPENDENCIES = \
 	host-python-mako
 
 UHD_CONF_OPTS = \
-	-DPYTHON_EXECUTABLE=$(HOST_DIR)/bin/python \
+	-DPYTHON_EXECUTABLE=$(HOST_DIR)/bin/python3 \
 	-DRUNTIME_PYTHON_EXECUTABLE=/usr/bin/python \
 	-DENABLE_C_API=ON \
 	-DENABLE_DOXYGEN=OFF \