Increase compiler warnings and fix them

src/mate/Makefile.am

@@ -1,4 +1,4 @@
-AM_CPPFLAGS = -Wall -Wextra -g $(all_includes)
+AM_CPPFLAGS = -Wall -Wextra -Wmissing-prototypes -g $(all_includes)
 
 bin_PROGRAMS = \
 	matesimulator

src/mate/matesimulator.c

@@ -50,8 +50,11 @@ wave_rec_t wave_tx_rec;
 
 /* dummy functions */
 int num_kanal = 1; /* only one channel used for debugging */
+void *get_sender_by_empfangsfrequenz(void);
 void *get_sender_by_empfangsfrequenz() { return NULL; }
+void display_measurements_add(void);
 void display_measurements_add() {}
+void display_measurements_update(void);
 void display_measurements_update() {}
 
 /* mate fill table according to eventphone's research */