GitLab

* doc/Makefile.in (clean):
* oldXMenu/Makefile.in (clean mostlyclean):
Simplify, for shorter command line.
* src/Makefile.in (AM_V_GEN, am__v_GEN_, am__v_GEN_0, am__v_GEN_1, AM_V_at)
(am__v_at_, am__v_at_0, am__v_at_1):  New macros, taken from Automake.
($(etc)/DOC, buildobj.h, gl-stamp): Use them.