diff --git a/srcpkgs/openmpi/template b/srcpkgs/openmpi/template
index 8fc5e38a6f1..587dbb7b02c 100644
--- a/srcpkgs/openmpi/template
+++ b/srcpkgs/openmpi/template
@@ -19,8 +19,9 @@ distfiles="${homepage}/software/ompi/v${version%.*}/downloads/${pkgname}-${versi
 checksum=b169e15f5af81bf3572db764417670f508c0df37ce86ff50deb56bd3acb43957
 nocross=yes  # libtool -rpath /usr/lib issue
 
-post_install() {
-	vlicense LICENSE
+post_extract() {
+	sed -i 's,sys/unistd.h,unistd.h,g' opal/include/opal/sys/cma.h
+	sed -i '1i#include <unistd.h>' opal/mca/pmix/pmix112/pmix/include/pmix_server.h
 }
 pre_configure() {
 	# used wrongly upstream? but nocross anyway
@@ -39,6 +40,9 @@ pre_configure() {
 
 	unset FC FC_FOR_BUILD
 }
+post_install() {
+	vlicense LICENSE
+}
 
 libopenmpi_package() {
 	short_desc+=" - runtime libraries"