Renamed .cvsignore files to .gitignore
Add top-level .gitignore
Refreshed aclocal.m4
Fix a warning from autoconf
-Wpointer-arithmetic => -Wpointer-arith

It looks like the name of this warning option changed some time in the
last nine years.
Remove GTK1.2 support, GTK2 hacks

None of which compile anymore.  Also the GTK 1.2 support break autoconf.
Work around WIFEXITED() not being const any longer

which now generates a warning.
Add missing g_strconcat() sentinels.
Update .gitignore