#2903: have pkg-config code path in `find_lib` set `FOO_RAW_INC_DIRS` and `FOO_RAW_LIB_DIRS`

Reporter: Roland Haas Status: new Milestone: Version: Type: bug Priority: major Component: Cactus

These variables contain the directory paths before the well-known system directories have been stripped out. To support this with pkg-config one has to avoid pkg-config itself doing the stripping by setting `PKG_CONFIG_ALLOW_SYSTEM_CFLAGS=1` and the same for LIBS.

See #2875 for a bit more context, though all ExternalLibraries `detect.sh` scripts that parse header files are affected.

-- Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2903/have-pkg-config-co...