Add windows prebuilt library path

This was in HOST_CROSS_GLOBAL_LD_DIRS, which is why it didn't get
translated over here, since Soong does not use global linking
directories. It's being moved to HOST_CROSS_GLOBAL_LDFLAGS so that it
can be shared.

Change-Id: Ie20670278a589ae3cf76e09de4079edfa800cf5b

cc/x86_windows_host.go

@@ -69,10 +69,12 @@ var (
 
 	windowsX86Ldflags = []string{
 		"-m32",
+		"-L${windowsGccRoot}/${windowsGccTriple}/lib32",
 	}
 
 	windowsX8664Ldflags = []string{
 		"-m64",
+		"-L${windowsGccRoot}/${windowsGccTriple}/lib64",
 	}
 )