From 39bd196481ba9ec6f5ef90a5e1b72976a3dc5e35 Mon Sep 17 00:00:00 2001
From: Lucas De Marchi <lucas.demarchi@intel.com>
Date: Mon, 16 May 2016 13:46:33 -0300
Subject: [PATCH] AP_GPS: do not use flexible array in union

We actually don't want a flexible array in this union, but rather a way
to access it byte by byte. This fixes the build for gcc >= 6

In file included from ../../libraries/AP_GPS/AP_GPS.cpp:24:0:
../../libraries/AP_GPS/AP_GPS_ERB.h:93:23: error: flexible array member in union
         uint8_t bytes[];
                       ^
compilation terminated due to -Wfatal-errors.

In file included from ../../libraries/AP_GPS/AP_GPS_ERB.cpp:22:0:
../../libraries/AP_GPS/AP_GPS_ERB.h:93:23: error: flexible array member in union
         uint8_t bytes[];
                       ^
compilation terminated due to -Wfatal-errors.

In file included from ../../libraries/AP_GPS/AP_GPS_MTK.cpp:25:0:
../../libraries/AP_GPS/AP_GPS_MTK.h:75:23: error: flexible array member in union
         uint8_t bytes[];
                       ^
compilation terminated due to -Wfatal-errors.

In file included from ../../libraries/AP_GPS/AP_GPS_MTK19.cpp:26:0:
../../libraries/AP_GPS/AP_GPS_MTK.h:75:23: error: flexible array member in union
         uint8_t bytes[];
                       ^
compilation terminated due to -Wfatal-errors.

In file included from ../../libraries/AP_GPS/AP_GPS_SIRF.cpp:22:0:
../../libraries/AP_GPS/AP_GPS_SIRF.h:101:23: error: flexible array member in union
         uint8_t bytes[];
                       ^
compilation terminated due to -Wfatal-errors.

In file included from ../../libraries/AP_GPS/AP_GPS_UBLOX.cpp:23:0:
../../libraries/AP_GPS/AP_GPS_UBLOX.h:387:23: error: flexible array member in union
         uint8_t bytes[];
                       ^
compilation terminated due to -Wfatal-errors.
---
 libraries/AP_GPS/AP_GPS_ERB.h   | 2 +-
 libraries/AP_GPS/AP_GPS_MTK.h   | 2 +-
 libraries/AP_GPS/AP_GPS_MTK19.h | 2 +-
 libraries/AP_GPS/AP_GPS_SIRF.h  | 2 +-
 libraries/AP_GPS/AP_GPS_UBLOX.h | 2 +-
 5 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/libraries/AP_GPS/AP_GPS_ERB.h b/libraries/AP_GPS/AP_GPS_ERB.h
index 8d04697111..5c0c3fc825 100644
--- a/libraries/AP_GPS/AP_GPS_ERB.h
+++ b/libraries/AP_GPS/AP_GPS_ERB.h
@@ -90,7 +90,7 @@ private:
         erb_stat stat;
         erb_dops dops;
         erb_vel vel;
-        uint8_t bytes[];
+        uint8_t bytes[1];
     } _buffer;
 
     enum erb_protocol_bytes {
diff --git a/libraries/AP_GPS/AP_GPS_MTK.h b/libraries/AP_GPS/AP_GPS_MTK.h
index e8ce210e3a..fa2188f125 100644
--- a/libraries/AP_GPS/AP_GPS_MTK.h
+++ b/libraries/AP_GPS/AP_GPS_MTK.h
@@ -72,7 +72,7 @@ private:
     // Receive buffer
     union PACKED {
         diyd_mtk_msg msg;
-        uint8_t bytes[];
+        uint8_t bytes[1];
     } _buffer;
 
     // Buffer parse & GPS state update
diff --git a/libraries/AP_GPS/AP_GPS_MTK19.h b/libraries/AP_GPS/AP_GPS_MTK19.h
index 43b08618a2..054a94c491 100644
--- a/libraries/AP_GPS/AP_GPS_MTK19.h
+++ b/libraries/AP_GPS/AP_GPS_MTK19.h
@@ -78,6 +78,6 @@ private:
     // Receive buffer
     union {
         diyd_mtk_msg msg;
-        uint8_t bytes[];
+        uint8_t bytes[1];
     } _buffer;
 };
diff --git a/libraries/AP_GPS/AP_GPS_SIRF.h b/libraries/AP_GPS/AP_GPS_SIRF.h
index 6c6f74bc90..8833c9ca7f 100644
--- a/libraries/AP_GPS/AP_GPS_SIRF.h
+++ b/libraries/AP_GPS/AP_GPS_SIRF.h
@@ -98,7 +98,7 @@ private:
     // Message buffer
     union {
         sirf_geonav nav;
-        uint8_t bytes[];
+        uint8_t bytes[1];
     } _buffer;
 
     bool        _parse_gps(void);
diff --git a/libraries/AP_GPS/AP_GPS_UBLOX.h b/libraries/AP_GPS/AP_GPS_UBLOX.h
index 2ea52abad0..c33316e9f1 100644
--- a/libraries/AP_GPS/AP_GPS_UBLOX.h
+++ b/libraries/AP_GPS/AP_GPS_UBLOX.h
@@ -384,7 +384,7 @@ private:
         ubx_rxm_rawx rxm_rawx;
 #endif
         ubx_ack_ack ack;
-        uint8_t bytes[];
+        uint8_t bytes[1];
     } _buffer;
 
     enum ubs_protocol_bytes {