python: build host-python with MAKE1

Building host-python in parallel sometimes causes "Bus error" during
the installation step on our autobuilders, such as:

  http://autobuild.buildroot.org/results/04bcc907c5e075fe1f39d4f49dcc50ec93708eb4/build-end.log

Extensive testing on one autobuilder has shown that building
host-python with MAKE1 work arounds this strange problem.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/python/python.mk

@@ -39,6 +39,14 @@ HOST_PYTHON_MAKE_ENV = \
 
 HOST_PYTHON_AUTORECONF = YES
 
+# Building host python in parallel sometimes triggers a "Bus error"
+# during the execution of "./python setup.py build" in the
+# installation step. It is probably due to the installation of a
+# shared library taking place in parallel to the execution of
+# ./python, causing spurious Bus error. Building host-python with
+# MAKE1 has shown to workaround the problem.
+HOST_PYTHON_MAKE = $(MAKE1)
+
 PYTHON_DEPENDENCIES  = host-python libffi
 
 HOST_PYTHON_DEPENDENCIES = host-expat host-zlib