Prior to pkg-config 0.24, --exists honored Requires and
Requires.private. This was regressed in commits 02d5ae3f and 669bfe2e,
which split the handling of Requires and Requires.private out more
correctly for other options. This adds exists to the group of options
that enable the Requires functionality.
Freedesktop #43149
Currently the check-missing passes the packages on the command line with
no options prior to running through --cflags/--libs, etc. Make this more
explicitly pass --exists since this is a much more common operation
performed from PKG_CHECK_MODULES.
The expected result of 0 when Requires or Requires.private is missing is
a regression from pre-0.24 pkg-config.
* pkg.[ch], main.c, check/check-missing: Don't recurse Requires at
all unless we need to. Add check. Again, thanks to Loïc Minier
for most of the idea and the implementation.
* pkg.[ch], parse.[ch], main.c, check/Makefile.am,
check/check-missing, check/missing-requires-private.pc:
Skip Requires.private unless we need to look at them for cflags.
Add test case. Thanks to Loïc Minier for most of the idea and the
implementation. Debian #475031