Disable usage of posix_spawn() inside LLVM.

Even though it's nice to use posix_spawn() instead of manually using
fork()/exec(), it's better to disable this. FreeBSD 7 doesn't support
this interface. When enabled, we can't build tblgen, which prevents us
from building FreeBSD 9 on 7.

Tested by:	raj

lib/clang/clang.build.mk

@@ -12,7 +12,7 @@ TARGET_ARCH?=	${MACHINE_ARCH}
 # XXX: 8.0, to keep __FreeBSD_cc_version happy
 CFLAGS+=-DLLVM_HOSTTRIPLE=\"${TARGET_ARCH}-undermydesk-freebsd9.0\" \
 	-DCLANG_VENDOR=\"FreeBSD\ \" -DSVN_REVISION=\"104832\" \
-	-DCLANG_VENDOR_SUFFIX=\"\ 20100612\"
+	-DCLANG_VENDOR_SUFFIX=\"\ 20100613\"
 
 .PATH:	${LLVM_SRCS}/${SRCDIR}
 

lib/clang/include/llvm/Config/config.h

@@ -270,7 +270,7 @@
 #define HAVE_OPENDIR 1
 
 /* Define to 1 if you have the `posix_spawn' function. */
-#define HAVE_POSIX_SPAWN 1
+/* #undef HAVE_POSIX_SPAWN */
 
 /* Define to 1 if you have the `powf' function. */
 #define HAVE_POWF 1