[Bug testsuite/85677] New: [openacc] gomp-constants.h not available in installed testing of libgomp

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85677

            Bug ID: 85677
           Summary: [openacc] gomp-constants.h not available in installed
                    testing of libgomp
           Product: gcc
           Version: 9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: testsuite
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vries at gcc dot gnu.org
  Target Milestone: ---

I've added quite a few "#include <gomp-constants.h>" to libgomp openacc
testcases in r259850.

That worked fine for buildarea testing, but broke those test-cases for
installed testing.

In the build-area testing setup, the compiler can find gomp-constants.h because
in libgomp.exp we find:
...
    if { $blddir != "" } {
        ...
        # The top-level include directory, for gomp-constants.h.
        lappend ALWAYS_CFLAGS "additional_flags=-I${srcdir}/../../include"
    }
...
but this line is not active for installed testing.