terragrunt: use glide rather than raw git

srcpkgs/terragrunt/template

@@ -6,13 +6,18 @@ build_style=go
 short_desc="A thin wrapper for Terraform that provides extra tools"
 maintainer="Andrea Brancaleoni <abc@pompel.me>"
 depends="terraform"
-hostmakedepends="git"
+hostmakedepends="glide"
 license="MIT"
 go_import_path="github.com/gruntwork-io/$pkgname"
 homepage="https://$go_import_path"
 distfiles="$homepage/archive/v$version.tar.gz"
 checksum=0b265cd3c7640d527fd453f92c19caf27125ed5e8b517aadb667bba026022ae8
 
+pre_build() {
+	cd $GOSRCPATH
+	glide install
+}
+
 post_install() {
 	vlicense LICENSE.txt
 }