Clarify XQuartz warning

Closes #24094.
exiftool 9.40

Closes #24135.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
gplcver: fix build with clang
memcacheq: fix build with clang
podofo 0.9.2
sipsak: fix build with clang
lysp 1.1
libopkele: fix build with clang
calcurse 3.1.4
ushare: fix build with clang
librsync: fix build with clang
Remove kelbt

Upstream is no longer active (see http://www.complang.org/kelbt), and it
doesn't build with clang.

Closes #24139.
jemalloc 3.4.1

Closes #24141.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>