Index: head/CHANGES
===================================================================
--- head/CHANGES
+++ head/CHANGES
@@ -10,6 +10,18 @@
 
 All ports committers are allowed to commit to this file.
 
+20160416:
+AUTHOR: jbeich@FreeBSD.org
+
+  Introducing CONFIGURE_OUTSOURCE. It changes HAS_CONFIGURE and GNU_CONFIGURE
+  by invoking configure, build and install stage outside of source tree e.g.,
+
+    $ mkdir ../.build
+    $ cd ../.build
+    $ ${OLDPWD}/configure
+    $ gmake
+    $ gmake install
+
 20160402:
 AUTHOR: bapt@FreeBSD.org
 
Index: head/Mk/bsd.port.mk
===================================================================
--- head/Mk/bsd.port.mk
+++ head/Mk/bsd.port.mk
@@ -780,6 +780,8 @@
 #				  configure stage will not do anything if this is not set.
 # GNU_CONFIGURE	- If set, you are using GNU configure (optional).  Implies
 #				  HAS_CONFIGURE.
+# CONFIGURE_OUTSOURCE - If set, this port builds in an empty ${CONFIGURE_WRKSRC}
+#				  not being under ${WRKSRC}.
 # CONFIGURE_WRKSRC
 #				- Directory to run configure in.
 #				  Default: ${WRKSRC}
@@ -1554,6 +1556,14 @@
 WRKSRC:=		${WRKSRC}/${WRKSRC_SUBDIR}
 .endif
 
+.if defined(CONFIGURE_OUTSOURCE)
+CONFIGURE_CMD?=		${WRKSRC}/${CONFIGURE_SCRIPT}
+CONFIGURE_WRKSRC?=	${WRKDIR}/.build
+BUILD_WRKSRC?=		${CONFIGURE_WRKSRC}
+INSTALL_WRKSRC?=	${CONFIGURE_WRKSRC}
+TEST_WRKSRC?=		${CONFIGURE_WRKSRC}
+.endif
+
 PATCH_WRKSRC?=	${WRKSRC}
 CONFIGURE_WRKSRC?=	${WRKSRC}
 BUILD_WRKSRC?=	${WRKSRC}
@@ -3334,6 +3344,7 @@
 	done
 .endif
 .if defined(HAS_CONFIGURE)
+	@${MKDIR} ${CONFIGURE_WRKSRC}
 	@(cd ${CONFIGURE_WRKSRC} && \
 	    ${SET_LATE_CONFIGURE_ARGS} \
 		if ! ${SETENV} CC="${CC}" CPP="${CPP}" CXX="${CXX}" \