[pushed] Darwin: Suppress adding embedded rpaths for earlier OS versions.

[Iain Sandoe <iains.gcc@gmail.com>]

The current setup leads to spurious test fails, where we are building for
macOS 10.4 or earlier.

Tested on x86_64, i868, powerpc Darwin, x86_64 Linux, pushed to trunk,
thanks
Iain

--- 8< ---

When we have @rpath support by virtue of the OS version we're hosting on
we still need to omit those rpath entries when targeting < 10.5 (or the
linker will complain).  To do this we (maybe ab-)use a property of the
spec function expansion that a non-null return value can be used as the
true input to a second spec (whereas, unfortunately, we cannot pass specs
to the version function at present).

gcc/ChangeLog:

	* config/darwin.h (DARWIN_RPATH_SPEC): Arrange for the %P spec
	to be conditional on macosx-version-min.

Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>
---
 gcc/config/darwin.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/gcc/config/darwin.h b/gcc/config/darwin.h
index e94a29c639c..cb96d67b3b1 100644
--- a/gcc/config/darwin.h
+++ b/gcc/config/darwin.h
@@ -612,8 +612,7 @@ extern GTY(()) int darwin_ms_struct;
    director as one being loaded.  */
 #define DARWIN_RPATH_SPEC \
   "%:version-compare(>= 10.5 mmacosx-version-min= -rpath) \
-   %:version-compare(>= 10.5 mmacosx-version-min= @loader_path) \
-   %P "
+   %{%:version-compare(>= 10.5 mmacosx-version-min= @loader_path): %P }"
 #else
 #define DARWIN_RPATH_SPEC ""
 #endif
-- 
2.39.2 (Apple Git-143)