system/i2c-tools: Use a single make job, build python modules.

Signed-off-by: Matteo Bernardini <ponce@slackbuilds.org>

system/i2c-tools/i2c-tools.SlackBuild

@@ -83,8 +83,11 @@ sed -i \
   -e "s|BUILD_STATIC_LIB\ ?=\ 1|BUILD_STATIC_LIB ?= 0|" \
   Makefile
 
-make
+make -j1
 make install DESTDIR=$PKG
+( cd py-smbus
+  python setup.py install --root=$PKG
+  if $(python3 -c 'import sys' 2>/dev/null); then python3 setup.py install --root=$PKG ; fi)
 
 find $PKG -print0 | xargs -0 file | grep -e "executable" -e "shared object" | grep ELF \
   | cut -f 1 -d : | xargs strip --strip-unneeded 2> /dev/null || true