package/go: pass CFLAGS/CXXFLAGS/LDFLAGS in HOST_GO_TARGET_ENV

HOST_GO_HOST_ENV is explicitly specifying
HOST_CGO_{CFLAGS,CXXFLAGS,LDFLAGS}, so let's do the same for target
packages.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/go/go.mk

@@ -55,6 +55,9 @@ HOST_GO_TARGET_ENV = \
 	GOCACHE="$(HOST_GO_TARGET_CACHE)" \
 	CC="$(TARGET_CC)" \
 	CXX="$(TARGET_CXX)" \
+	CGO_CFLAGS="$(TARGET_CFLAGS)" \
+	CGO_CXXFLAGS="$(TARGET_CXXFLAGS)" \
+	CGO_LDFLAGS="$(TARGET_LDFLAGS)" \
 	GOTOOLDIR="$(HOST_GO_TOOLDIR)"
 
 # The go compiler's cgo support uses threads.  If BR2_TOOLCHAIN_HAS_THREADS is