Add HC_API_CALL to a few functions

On 32-bit MinGW, clang was throwing errors about this.

64-bit MinGW and regular MSYS does not throw warnings after the change.

src/autotune.c

@@ -272,7 +272,7 @@ static int autotune (hashcat_ctx_t *hashcat_ctx, hc_device_param_t *device_param
   return 0;
 }
 
-void *thread_autotune (void *p)
+HC_API_CALL void *thread_autotune (void *p)
 {
   thread_param_t *thread_param = (thread_param_t *) p;