Various fixes for mingw

plugins/sysinfo/win32/backend.c

@@ -30,14 +30,7 @@
 
 #include "../format.h"
 
-static int command_callback (char *word[], char *word_eol[], void *user_data);
-
-void print_info (void);
-
-guint64 hdd_capacity;
-guint64 hdd_free_space;
-char *read_hdd_info (IWbemClassObject *object);
-char *get_memory_info (void);
+static char *get_memory_info (void);
 
 char *
 sysinfo_backend_get_sound (void)
@@ -98,11 +91,6 @@ sysinfo_backend_get_os (void)
 	return sysinfo_get_os ();
 }
 
-static int get_cpu_arch (void)
-{
-	return sysinfo_get_cpu_arch ();
-}
-
 static char *get_memory_info (void)
 {
 	MEMORYSTATUSEX meminfo = { 0 };