Wire up both gitk and git-gui in Meson as subprojects. These two
programs should be the last missing pieces for feature compatibility
with our Makefile for distributors.
Note that Meson expects subprojects to live in the "subprojects/"
directory. Create symlinks to fulfill this requirement.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
