What is the correct way to require a specific version of clang?

[Yuri]

There is no such thing as USES=clang:38, for example.

When I try this:

.include <bsd.port.options.mk>

.if ${OPSYS} == FreeBSD && ${OSVERSION} < 1100000
BUILD_DEPENDS=  clang38:lang/clang38
RUN_DEPENDS=    clang38:lang/clang38
CC=             clang38
CXX=            clang++38

.endif


It prints warnings in pourdriere 10i386 machine:

clang38: not found
make: "/usr/ports/Mk/Uses/compiler.mk" line 69: warning: "clang38 
--version" returned non-zero status
make: "/usr/ports/Mk/Uses/compiler.mk" line 112: warning: "clang++38 
-### /dev/null 2>&1" returned non-zero status


How to do this without such messages?


Thank you,

Yuri