--- a/usr/portage/eclass/cmake-utils.eclass	2018-01-10 10:42:27.820101300 +0100
+++ b/usr/portage/eclass/cmake-utils.eclass	2018-01-11 12:48:18.248058400 +0100
@@ -576,14 +576,14 @@
 
 	if [[ ${EPREFIX} ]]; then
 		cat >> "${build_rules}" <<- _EOF_ || die
-			# in Prefix we need rpath and must ensure cmake gets our default linker path
-			# right ... except for Darwin hosts
-			IF (NOT APPLE)
-			SET (CMAKE_SKIP_RPATH OFF CACHE BOOL "" FORCE)
-			SET (CMAKE_PLATFORM_REQUIRED_RUNTIME_PATH "${EPREFIX}/usr/${CHOST}/lib/gcc;${EPREFIX}/usr/${CHOST}/lib;${EPREFIX}/usr/$(get_libdir);${EPREFIX}/$(get_libdir)"
-			CACHE STRING "" FORCE)
+			# Be sure *not* to have WIN32 set on cygwin hosts
+			IF (CYGWIN)
+			SET (WIN32 OFF CACHE BOOL "" FORCE)
+			ENDIF (CYGWIN)
 
-			ELSE ()
+			# in Prefix we need rpath and must ensure cmake gets our default linker path
+			# right ... except for Darwin and Cygwin hosts
+			IF (APPLE OR CYGWIN)
 
 			SET(CMAKE_PREFIX_PATH "${EPREFIX}/usr" CACHE STRING "" FORCE)
 			SET(CMAKE_MACOSX_RPATH ON CACHE BOOL "" FORCE)
@@ -591,7 +591,13 @@
 			SET(CMAKE_SKIP_RPATH OFF CACHE BOOL "" FORCE)
 			SET(CMAKE_INSTALL_RPATH_USE_LINK_PATH TRUE CACHE BOOL "" FORCE)
 
-			ENDIF (NOT APPLE)
+			ELSE ()
+
+			SET (CMAKE_SKIP_RPATH OFF CACHE BOOL "" FORCE)
+			SET (CMAKE_PLATFORM_REQUIRED_RUNTIME_PATH "${EPREFIX}/usr/${CHOST}/lib/gcc;${EPREFIX}/usr/${CHOST}/lib;${EPREFIX}/usr/$(get_libdir);${EPREFIX}/$(get_libdir)"
+			CACHE STRING "" FORCE)
+
+			ENDIF (APPLE OR CYGWIN)
 		_EOF_
 	fi