Index: Mk/bsd.port.mk
===================================================================
--- Mk/bsd.port.mk
+++ Mk/bsd.port.mk
@@ -1061,6 +1061,11 @@
 _PORTS_DIRECTORIES+=	${PKG_DBDIR} ${PREFIX} ${WRKDIR} ${EXTRACT_WRKDIR} \
 						${STAGEDIR}${PREFIX} ${WRKDIR}/pkg
 
+# Ensure .CURDIR does not contain a trailing /, otherwise something like
+# make -C /usr/ports/category/port/
+# can result in a failed build.
+.CURDIR:=	${.CURDIR:tA}
+
 # make sure bmake treats -V as expected
 .MAKE.EXPAND_VARIABLES= yes