dev-libs/newt: fix python optionality

- we can't call python_foreach_impl if all targets are unset, which is
  permitted if python is optional
- somehow I switched back to calling with EPYTHON instead of versions,
  this was plainly wrong
- $(use_with) *must* be additionally quoted if withval itself is quoted
  and contains spaces, or we lose the spaces again

Closes: https://bugs.gentoo.org/955709
Signed-off-by: Eli Schwartz <eschwartz@gentoo.org>

dev-libs/newt/newt-0.52.25-r1.ebuild

@@ -66,10 +66,10 @@ src_configure() {
 	getversions() {
 		versions+="${EPYTHON} "
 	}
-	python_foreach_impl getversions
+	use python && python_foreach_impl getversions
 
 	econf \
-		$(use_with python '' "${EPYTHON}") \
+		"$(use_with python '' "${versions}")" \
 		$(use_with gpm gpm-support) \
 		$(use_with tcl) \
 		$(use_enable nls)