package/go: add double quotes around TARGET_CC/TARGET_CXX

Using double quotes around TARGET_CC/TARGET_CXX is mandatory, since
they are composed of several words when ccache support is enabled.

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

package/go/go.mk

@@ -40,8 +40,8 @@ HOST_GO_TOOLDIR = $(HOST_GO_ROOT)/pkg/tool/linux_$(GO_GOARCH)
 HOST_GO_TARGET_ENV = \
 	GOARCH=$(GO_GOARCH) \
 	GOROOT="$(HOST_GO_ROOT)" \
-	CC=$(TARGET_CC) \
-	CXX=$(TARGET_CXX) \
+	CC="$(TARGET_CC)" \
+	CXX="$(TARGET_CXX)" \
 	GOTOOLDIR="$(HOST_GO_TOOLDIR)"
 
 # The go compiler's cgo support uses threads.  If BR2_TOOLCHAIN_HAS_THREADS is
@@ -74,8 +74,8 @@ HOST_GO_MAKE_ENV = \
 	CC=$(HOSTCC_NOCCACHE)
 
 HOST_GO_TARGET_CC = \
-	CC_FOR_TARGET=$(TARGET_CC) \
-	CXX_FOR_TARGET=$(TARGET_CXX)
+	CC_FOR_TARGET="$(TARGET_CC)" \
+	CXX_FOR_TARGET="$(TARGET_CXX)"
 
 HOST_GO_HOST_CC = \
 	CC_FOR_TARGET=$(HOSTCC_NOCCACHE) \