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, 6 insertions, 0 deletions

diff --git a/tools/build/options/WITHOUT_GNUCXX b/tools/build/options/WITHOUT_GNUCXX
new file mode 100644
index 0000000..ce10636
--- /dev/null
+++ b/tools/build/options/WITHOUT_GNUCXX
@@ -0,0 +1,3 @@
+.\" $FreeBSD$
+Do not build the GNU C++ stack (g++, libstdc++).
+This is the default on platforms where clang is the system compiler.
diff --git a/tools/build/options/WITH_GNUCXX b/tools/build/options/WITH_GNUCXX
new file mode 100644
index 0000000..c49e7cd
--- /dev/null
+++ b/tools/build/options/WITH_GNUCXX
@@ -0,0 +1,3 @@
+.\" $FreeBSD$
+Build the GNU C++ stack (g++, libstdc++).
+This is the default on platforms where gcc is the system compiler.