prereq-build: require python3-distutils

Debian and Ubuntu ship a python3-minimal package which does not include
the distutils module. This is not supported by upstream and can be
considered a broken python distribution.

In practice, many scripts depend on said module, and this is a reoccuring
pain point for building various OpenWrt packages.

Require and check for said module, enough time has been wasted on this.

A list of just the most recent issues:
https://github.com/openwrt/packages/pull/16304
https://github.com/openwrt/packages/pull/16027
https://github.com/openwrt/packages/pull/15443
https://github.com/openwrt/packages/pull/14394
https://github.com/openwrt/packages/pull/12909
https://github.com/openwrt/packages/issues/12443
https://github.com/openwrt/packages/pull/11035
https://github.com/openwrt/packages/issues/10993

Signed-off-by: Andre Heider <[email protected]>

include/prereq-build.mk

@@ -170,6 +170,10 @@ $(eval $(call SetupHostCommand,python3,Please install Python >= 3.6, \
 	python3.6 -V 2>&1 | grep 'Python 3', \
 	python3 -V 2>&1 | grep -E 'Python 3\.[6-9]\.?'))
 
+$(eval $(call TestHostCommand,python3-distutils, \
+	Please install the Python3 distutils module, \
+	$(STAGING_DIR_HOST)/bin/python3 -c 'import distutils'))
+
 $(eval $(call SetupHostCommand,git,Please install Git (git-core) >= 1.7.12.2, \
 	git --exec-path | xargs -I % -- grep -q -- --recursive %/git-submodule))