On platforms where clang is the default compiler, don't build gcc or libstdc++.

To enable them, set WITH_GCC and WITH_GNUCXX in src.conf.
Make clang default to using libc++ on FreeBSD 10.
Bumped __FreeBSD_version for the change.

GCC is still enabled on PC98, because the PC98 bootloader requires GCC to build
(or, at least, hard-codes the use of gcc into its build).

Thanks to everyone who helped make the ports tree ready for this (and bapt
for coordinating them all).  Also to imp for reviewing this and working on the
forward-porting of the changes in our gcc so that we're getting to a much
better place with regard to external toolchains.

Sorry to all of the people who helped who I forgot to mention by name.

Reviewed by:	bapt, imp, dim, ...

2 files changed, 7 insertions, 2 deletions

diff --git a/gnu/lib/Makefile b/gnu/lib/Makefile
index 6750403d66c5..50797fced309 100644
--- a/gnu/lib/Makefile
+++ b/gnu/lib/Makefile
@@ -10,7 +10,7 @@ SUBDIR+= libssp
 
 # libsupc++ uses libstdc++ headers, although 'make includes' should
 # have taken care of that already.
-.if ${MK_CXX} != "no"
+.if ${MK_GNUCXX} != "no"
 SUBDIR+= libstdc++ libsupc++
 .endif
 
diff --git a/gnu/usr.bin/cc/Makefile b/gnu/usr.bin/cc/Makefile
index efb548aaf62e..bf6d20c79ce4 100644
--- a/gnu/usr.bin/cc/Makefile
+++ b/gnu/usr.bin/cc/Makefile
@@ -12,7 +12,12 @@ SUBDIR+= cpp
 .endif
 
 .if ${MK_CXX} != "no"
-SUBDIR+= cc1plus c++ c++filt
+.if ${MK_GNUCXX} != "no"
+SUBDIR+= cc1plus c++ 
+.endif
+# This should be moved into the above block once c++filt from elftoolchain or
+# similar is provided.
+SUBDIR+= c++filt
 .endif
 
 .if ${MK_GCOV} != "no"