--- Mk/bsd.port.mk.orig	2011-09-06 08:55:19.000000000 +0200
+++ Mk/bsd.port.mk	2011-09-06 08:59:52.000000000 +0200
@@ -1930,8 +1930,10 @@
 X_FONTS_ALIAS_PORT=	${PORTSDIR}/x11-fonts/font-alias
 
 .if defined(USE_IMAKE)
-CONFIGURE_ENV+=		IMAKECPP="${CPP}"
-MAKE_ENV+=		IMAKECPP="${CPP}"
+# IMAKE is dated and touchy about invoking cpp, even sensible stuff like
+# "clang -E" fails.
+CONFIGURE_ENV+=		IMAKECPP="cpp"
+MAKE_ENV+=		IMAKECPP="cpp"
 MAKE_FLAGS?=		CC="${CC}" CXX="${CXX}"
 BUILD_DEPENDS+=		imake:${X_IMAKE_PORT}
 .endif