Fix native powerpc64 build of lib32 with in-tree GCC.

- This was broken by r300350 and r300885.
- Add some comments around the external GCC logic since it is spread out
  and in need of some cleanup.
- The problem was that X_COMPILER_TYPE is always defined from CC->XCC's
  default, so if /usr/bin/cc is GCC (as it is on native powerpc64) then
  X_COMPILER_TYPE was getting GCC and triggering the external logic in
  Makefile.libcompat.  It was intended to always provide -isystem with
  GCC since --sysroot is used into the lib32 sysroot which won't modify
  the header path without the -isystem.  The use of the libc++/std=c++11
  override was only intended to be used for external compilers though
  (more accurately GCC 4.8+ but that's a separate assumption to
  cleanup).  Apply the same logic from Makefile.inc1 to Makefile.libcompat
  to only add the libc++ override when needed for external compilers.

Pointyhat to:	bdrewery
Tested with:	native ppc64 (swills), universe, ppc64 xtoolchain,
		amd64 xtoolchain, sparc64 cross-build of ppc64 (host GCC 4.2)
Reported by:	andreast, swills
Approved by:	re (gjb)
Sponsored by:	EMC / Isilon Storage Division

1 files changed, 3 insertions, 0 deletions

diff --git a/share/mk/src.opts.mk b/share/mk/src.opts.mk
index e3ef419..790a466 100644
--- a/share/mk/src.opts.mk
+++ b/share/mk/src.opts.mk
@@ -419,6 +419,9 @@ MK_LLDB:=	no
 # gcc 4.8 and newer supports libc++, so suppress gnuc++ in that case.
 # while in theory we could build it with that, we don't want to do
 # that since it creates too much confusion for too little gain.
+# XXX: This is incomplete and needs X_COMPILER_TYPE/VERSION checks too
+#      to prevent Makefile.inc1 from bootstrapping unneeded dependencies
+#      and to support 'make delete-old' when supplying an external toolchain.
 .if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 40800
 MK_GNUCXX:=no
 MK_GCC:=no