package/pkg-golang: add cflags/ldflags to GO_HOST_ENV

If a go host package is built using cgo, it needs access
to HOST_CFLAGS/HOST_LDFLAGS to utilize host packages it
might depend on.

Signed-off-by: Mirza Krak <mirza.krak@northern.tech>
Acked-by: Adam Duskett <aduskett@gmail.com>
Tested-by: Adam Duskett <aduskett@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/pkg-golang.mk

@@ -35,6 +35,8 @@ GO_TARGET_ENV = \
 	$(GO_COMMON_ENV)
 
 GO_HOST_ENV = \
+	CGO_CFLAGS="$(HOST_CFLAGS)" \
+	CGO_LDFLAGS="$(HOST_LDFLAGS)" \
 	$(GO_COMMON_ENV)
 
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