Define several extra macros in bsd.sys.mk and sys/conf/kern.pre.mk, to

get rid of testing explicitly for clang (using ${CC:T:Mclang}) in
individual Makefiles.

Instead, use the following extra macros, for use with clang:
- NO_WERROR.clang       (disables -Werror)
- NO_WCAST_ALIGN.clang  (disables -Wcast-align)
- NO_WFORMAT.clang	(disables -Wformat and friends)
- CLANG_NO_IAS		(disables integrated assembler)
- CLANG_OPT_SMALL	(adds flags for extra small size optimizations)

As a side effect, this enables setting CC/CXX/CPP in src.conf instead of
make.conf!  For clang, use the following:

CC=clang
CXX=clang++
CPP=clang-cpp

MFC after:	2 weeks

1 files changed, 1 insertions, 3 deletions

diff --git a/lib/libsm/Makefile b/lib/libsm/Makefile
index 661e87a6e7aa..f2f19fb4cf4a 100644
--- a/lib/libsm/Makefile
+++ b/lib/libsm/Makefile
@@ -18,12 +18,10 @@ CFLAGS+=${SENDMAIL_CFLAGS}
 
 WARNS?=	2
 
-.if ${CC:T:Mclang} == "clang"
 # Unfortunately, clang gives warnings about sendmail code that cannot
 # be turned off yet.  Since this is contrib code, and we don't really
 # care about the warnings, just make them non-fatal for now.
-NO_WERROR=
-.endif
+NO_WERROR.clang=
 
 LIB=	sm