[host][darwin][cgo] Fix #832 work around once-again broken go modules not including C files

Supersedes #885 by @afontaine

host/host_darwin_cgo.go

@@ -4,9 +4,7 @@
 package host
 
 // #cgo LDFLAGS: -framework IOKit
-// #include <stdio.h>
+// #include "smc_darwin.h"
-// #include <string.h>
-// #include "include/smc.c"
 import "C"
 import "context"
 

host/smc_darwin.c

@@ -1,4 +1,6 @@
-#include "smc.h"
+#include <stdio.h>
+#include <string.h>
+#include "smc_darwin.h"
 
 #define IOSERVICE_SMC "AppleSMC"
 #define IOSERVICE_MODEL "IOPlatformExpertDevice"