sci-visualization/gr: Only create symlink if target exists

Closes: https://bugs.gentoo.org/750056
Package-Manager: Portage-3.0.8, Repoman-3.0.2
Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>

sci-visualization/gr/gr-0.50.0-r2.ebuild

@@ -68,7 +68,7 @@ src_install() {
 	echo "LDPATH=/usr/gr/$(get_libdir)" >> "${T}/99gr"
 	doenvd "${T}/99gr"
 
-	dosym ../gr/bin/gksqt /usr/bin/gksqt
+	[[ -f "${ED}/usr/gr/bin/gksqt" ]] && dosym ../gr/bin/gksqt /usr/bin/gksqt
 
 	elog "${P} relies on the environment variable GRDIR. If you want to use it in a running shell,"
 	elog "e.g. with dev-lang/julia, then run \"source /etc/profile\" first."