Be more careful than just exporting CPPFLAGS (or not) to sub-
configure scripts. This fixes a bug in which --enable-visibility
would cause PRRTE's configure to fail, because the top-level
configure added -Wmissing-prototypes to CPPFLAGS and then
the subconfigure added -Werror at one point. In general,
blindly exporting all the CPPFLAGS OMPI adds was a bad idea, so
we instead only export precious variables if they were
set in the calling environment, on the command line of the
top-level configure, or explicitly added to the sub-
configure environment (like CPPFLAGS for PMIx/PRRTE).
Add some envirnoment scrubbing/saving/restore wrappers and
modify PAC_CONFIG_SUBDIR_ARGS to play a little nicer with
precious variables so that this all works.
Signed-off-by: Brian Barrett <bbarrett@amazon.com>
With Open MPI 5.0, the decision was made to stop building 3rd-party
packages, such as Libevent, HWLOC, PMIx, and PRRTE as MCA components
and instead 1) start relying on external libraries whenever possible
and 2) Open MPI builds the 3rd party libraries (if needed) as
independent libraries, rather than linked into libopen-pal.
This patch is the first step in that process, providing foundational
changes required for supporting 3rd-party packages, such as changes
to autogen.pl, the top-level Makefile.am, and introducing two
Autoconf macros to support running sub-configure scripts; one
supporting source in tarball form and the other supporting
source in a sub-tree.
Signed-off-by: Brian Barrett <bbarrett@amazon.com>
