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

2 files changed, 2 insertions, 6 deletions

diff --git a/libexec/mail.local/Makefile b/libexec/mail.local/Makefile
index de490fb..1487dec 100644
--- a/libexec/mail.local/Makefile
+++ b/libexec/mail.local/Makefile
@@ -12,12 +12,10 @@ CFLAGS+=-I${SENDMAIL_DIR}/include -I.
 WARNS?=	2
 WFORMAT=0
 
-.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=
 
 LIBSMDIR=	${.OBJDIR}/../../lib/libsm
 LIBSM=		${LIBSMDIR}/libsm.a
diff --git a/libexec/smrsh/Makefile b/libexec/smrsh/Makefile
index 7080fba..0de820d 100644
--- a/libexec/smrsh/Makefile
+++ b/libexec/smrsh/Makefile
@@ -17,12 +17,10 @@ LDADD=	${LIBSM}
 
 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=
 
 SRCS+=	sm_os.h
 CLEANFILES+=sm_os.h