Fix flexible array usage gcc-ism

(cherry picked from commit 74bc4880)

Conflicts:

	src/stream_output/sap.c

modules/services_discovery/sap.c

@@ -212,7 +212,7 @@ struct  sdp_t
 struct attribute_t
 {
     const char *value;
-    char name[0];
+    char name[];
 };
 
 struct sap_announce_t

src/misc/block.c

@@ -40,7 +40,7 @@ struct block_sys_t
 {
     block_t     self;
     size_t      i_allocated_buffer;
-    uint8_t     p_allocated_buffer[0];
+    uint8_t     p_allocated_buffer[];
 };
 
 #ifndef NDEBUG

src/misc/win32_specific.c

@@ -129,7 +129,7 @@ typedef struct
 {
   int argc;
   int enqueue;
-  char data[0];
+  char data[];
 } vlc_ipc_data_t;
 
 void system_Configure( libvlc_int_t *p_this, int *pi_argc, const char *ppsz_argv[] )