build-sys: Fix indentation of trailing \ in Makefile.am
build-sys: Fix indentation of trailing \ in Makefile.am

Make sure they are indented with tabs and aligned.

fgouget/xf86-video-qxl,fgouget/xf86-video-qxl,fgouget/xf86-video-qxl,fgouget/xf86-video-qxl