[host][mkfs-msdosfs][netprotocol] _BSD_SOURCE -> _GNU_SOURCE

The _BSD_SOURCE feature-test macro is deprecated and newer
in glibc versions the headers generate a warning for using it.
_GNU_SOURCE enables everything that does and more, and our
code is compatible with it.

Change-Id: Ic049fd835d77f17e81faae0ac3349565a5b6f9b6

system/host/mkfs-msdosfs/rules.mk

@@ -6,7 +6,7 @@ LOCAL_DIR := $(GET_LOCAL_DIR)
 
 MKMSDOS_DIR := third_party/uapp/mkfs-msdosfs
 
-MODULE_DEFINES := _XOPEN_SOURCE _BSD_SOURCE
+MODULE_DEFINES := _XOPEN_SOURCE _GNU_SOURCE
 
 MODULE := $(LOCAL_DIR)
 

system/host/netprotocol/netprotocol.c

@@ -4,7 +4,7 @@
 
 #define _POSIX_C_SOURCE 200809L
 #define _DARWIN_C_SOURCE
-#define _BSD_SOURCE
+#define _GNU_SOURCE
 
 #include "netprotocol.h"