[patch] the patch created by me. It should solve the problem.

numpy-1.14.5.ebuild.patch (text/plain), 614 bytes, created by ZongyuZ on 2019-06-20 14:21:37 UTC

--- /usr/portage/dev-python/numpy/numpy-1.14.5.ebuild	2019-06-05 19:39:35.000000000 +0800
+++ ./numpy-1.14.5.ebuild	2019-06-20 22:11:30.970571687 +0800
@@ -67,10 +67,11 @@
 python_prepare_all() {
 	if use lapack; then
 		append-ldflags "$($(tc-getPKG_CONFIG) --libs-only-other cblas lapack)"
+		local incdir="${EPREFIX}"/usr/include
 		local libdir="${EPREFIX}"/usr/$(get_libdir)
 		cat >> site.cfg <<-EOF || die
 			[blas]
-			include_dirs = $(pc_incdir cblas)
+			include_dirs = $(pc_incdir cblas):${incdir}
 			library_dirs = $(pc_libdir cblas blas):${libdir}
 			blas_libs = $(pc_libs cblas blas)
 			[lapack]