Readd gopath tweaks to function in makepkg. Only for gcc-go

.go/src

@@ -0,0 +1 @@
+../vendor

Makefile

@@ -18,6 +18,7 @@ BINNAME := yay
 PACKAGE := ${PKGNAME}_${VERSION}_${ARCH}
 
 ifneq (,$(findstring gccgo,$(GOCC)))
+	export GOPATH=$(shell pwd)/.go
 	LDFLAGS := -gccgoflags '-s -w'
 	MOD :=
 endif