[ports/devel/boehm-gc] PTHREAD_LIBS clean

[Norikatsu Shigemura]

	I found a problem to not use PTHREAD_LIBS.  Please commit following
	patch.

Index: Makefile
===================================================================
RCS file: /home/pcvs/ports/devel/boehm-gc/Makefile,v
retrieving revision 1.53
diff -u -r1.53 Makefile
--- Makefile	1 Feb 2007 02:41:24 -0000	1.53
+++ Makefile	1 Feb 2007 08:57:05 -0000
@@ -31,10 +31,10 @@
 CONFIGURE_ARGS+=	--enable-threads=posix --enable-thread-local-alloc
 .if ${OSVERSION} < 502102
 CONFIGURE_ENV=	CFLAGS="${CFLAGS} ${PTHREAD_CFLAGS}" \
-		LIBS="${LIBS} -lc_r"
+		LIBS="${LIBS} ${PTHREAD_LIBS:C/-pthread/-lc_r/}"
 .else
 CONFIGURE_ENV=	CFLAGSS="${CFLAGS} ${PTHREAD_CFLAGS}" \
-		LIBS="${LIBS} -lpthread"
+		LIBS="${LIBS} ${PTHREAD_LIBS:C/-pthread/-lpthread/}"
 .endif
 .if defined(WITH_PARALLEL_MARK)
 CONFIGURE_ARGS+=	--enable-parallel-mark