--- tk-8.6.5.ebuild.old	2016-04-16 18:08:08.000000000 -0400
+++ tk-8.6.5.ebuild	2016-04-25 00:16:44.908243238 -0400
@@ -82,6 +82,12 @@
 }
 
 multilib_src_configure() {
+	# We went ahead and deleted the whole compat/ subdir which means
+	# the configure tests to detect broken versions need to pass (else
+	# we'll fail to build).  This comes up when cross-compiling, but
+	# might as well get a minor configure speed up normally.
+	export tcl_cv_strtod_buggy="no"
+
 	local mylibdir=$(get_libdir)
 
 	econf \