Support, to the extent we generate proper command lines, compiling

with clang 3.3. Useful for test building -current on a -stable system
in individual directories. Potentially useful if we ever want to
support, say, gcc 4.8 or 4.9's new warnings when building with an
external toolchain (but such support not yet committed). Document
the bsd.compiler.mk interface.

2 files changed, 31 insertions, 9 deletions

diff --git a/share/mk/bsd.compiler.mk b/share/mk/bsd.compiler.mk
index bb1229b..a4f3fec 100644
--- a/share/mk/bsd.compiler.mk
+++ b/share/mk/bsd.compiler.mk
@@ -1,27 +1,46 @@
 # $FreeBSD$
 
+# Setup variables for the compiler
+#
+# COMPILTER_TYPE is the major type of compiler. Currently gcc and clang support
+# automatic detetion. Other compiler types can be shoe-horned in, but require explicit
+# setting of the compiler type. The compiler type can also be set explicitly if, say,
+# you install gcc as clang...
+#
+# COMPILER_VERSION is a numeric constant equal to major * 10000 + minor * 100 + tiny. It
+# too can be overriden on the command line. When testing it, be sure to make sure that you
+# are limiting the test to a specific compiler. Testing against 30300 for gcc likely isn't
+# what you wanted (since versions of gcc prior to 4.2 likely have no prayer of working).
+#
+# COMPILER_FEATURES will contain one or more of the following, based on compiler support
+# for that feature: c++11 (supports full (or nearly full) C++11 programming environment).
+#
+# This file may be included multiple times, but only has effect the first time.
+#
+
 .if !target(__<bsd.compiler.mk>__)
 __<bsd.compiler.mk>__:
 
+_v!=	${CC} --version
 .if !defined(COMPILER_TYPE)
 . if ${CC:T:Mgcc*}
 COMPILER_TYPE:=	gcc  
 . elif ${CC:T:Mclang}
 COMPILER_TYPE:=	clang
-. else
-_COMPILER_VERSION!=	${CC} --version
-.  if ${_COMPILER_VERSION:Mgcc}
+. elif ${_v:Mgcc}
 COMPILER_TYPE:=	gcc
-.  elif ${_COMPILER_VERSION:M\(GCC\)}
+. elif ${_v:M\(GCC\)}
 COMPILER_TYPE:=	gcc
-.  elif ${_COMPILER_VERSION:Mclang}
+. elif ${_v:Mclang}
 COMPILER_TYPE:=	clang
-.  else
+. else
 .error Unable to determine compiler type for ${CC}.  Consider setting COMPILER_TYPE.
-.  endif
-.  undef _COMPILER_VERSION
 . endif
 .endif
+.if !defined(COMPILER_VERSION)
+COMPILER_VERSION!=echo ${_v:M[1-9].[0-9]*} | awk -F. '{print $$1 * 10000 + $$2 * 100 + $$3;}'
+.endif
+.undef _v
 
 .if ${COMPILER_TYPE} == "clang"
 COMPILER_FEATURES=	c++11
diff --git a/share/mk/bsd.sys.mk b/share/mk/bsd.sys.mk
index 8b892a9..7150f2f 100644
--- a/share/mk/bsd.sys.mk
+++ b/share/mk/bsd.sys.mk
@@ -64,7 +64,10 @@ CWARNFLAGS+=	-Wno-pointer-sign
 # Clang has more warnings enabled by default, and when using -Wall, so if WARNS
 # is set to low values, these have to be disabled explicitly.
 .if ${WARNS} <= 6
-CWARNFLAGS.clang+=	-Wno-empty-body -Wno-string-plus-int -Wno-unused-const-variable
+CWARNFLAGS.clang+=	-Wno-empty-body -Wno-string-plus-int
+.if ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} > 30300
+CWARNFLAGS.clang+= -Wno-unused-const-variable
+.endif
 .endif # WARNS <= 6
 .if ${WARNS} <= 3
 CWARNFLAGS.clang+=	-Wno-tautological-compare -Wno-unused-value\