Move extern declarations for bgscan modules into a header file

This gets rid of number of sparse warnings and also allows the
compatibility of the declarations to be verified.

Signed-off-by: Jouni Malinen <j@w1.fi>

wpa_supplicant/bgscan.c

@@ -13,12 +13,6 @@
 #include "config_ssid.h"
 #include "bgscan.h"
 
-#ifdef CONFIG_BGSCAN_SIMPLE
-extern const struct bgscan_ops bgscan_simple_ops;
-#endif /* CONFIG_BGSCAN_SIMPLE */
-#ifdef CONFIG_BGSCAN_LEARN
-extern const struct bgscan_ops bgscan_learn_ops;
-#endif /* CONFIG_BGSCAN_LEARN */
 
 static const struct bgscan_ops * bgscan_modules[] = {
 #ifdef CONFIG_BGSCAN_SIMPLE

wpa_supplicant/bgscan.h

@@ -39,6 +39,15 @@ void bgscan_notify_signal_change(struct wpa_supplicant *wpa_s, int above,
 				 int current_signal, int current_noise,
 				 int current_txrate);
 
+/* Available bgscan modules */
+
+#ifdef CONFIG_BGSCAN_SIMPLE
+extern const struct bgscan_ops bgscan_simple_ops;
+#endif /* CONFIG_BGSCAN_SIMPLE */
+#ifdef CONFIG_BGSCAN_LEARN
+extern const struct bgscan_ops bgscan_learn_ops;
+#endif /* CONFIG_BGSCAN_LEARN */
+
 #else /* CONFIG_BGSCAN */
 
 static inline int bgscan_init(struct wpa_supplicant *wpa_s,