Description of problem:
Mingw's definition of struct in6_addr requires multiple levels of {} to silence gcc's -Wmissing-braces; however, the definition in <ws2tcpip.h> lacks these.  It would also be nice if mingw could provide the standardized <netinet/in.h> as the POSIX name for getting at these macros.

Version-Release number of selected component (if applicable):
mingw32-headers-3.1.0-1.fc20.noarch

How reproducible:
100%

Steps to Reproduce:
1. $ cat a.c
#ifdef __linux__
#include <netinet/in.h>
#else
#include <ws2tcpip.h>
#endif
int foo(void) {
  struct in6_addr a = IN6ADDR_ANY_INIT;
  struct in6_addr b = IN6ADDR_LOOPBACK_INIT;
  return IN6_IS_ADDR_UNSPECIFIED(&a) + IN6_IS_ADDR_LOOPBACK(&b);
}

2. $ gcc -c -o a.o -Wall -Wmissing-braces a.c

3. $ i686-w64-mingw32-gcc -c -o a.o -Wall -Wmissing-braces a.c

Actual results:
2 is silent, 3 spews:

a.c: In function 'foo':
a.c:7:10: warning: missing braces around initializer [-Wmissing-braces]
   struct in6_addr a = IN6ADDR_ANY_INIT;
          ^
a.c:7:10: warning: (near initialization for 'a.u') [-Wmissing-braces]
a.c:8:10: warning: missing braces around initializer [-Wmissing-braces]
   struct in6_addr b = IN6ADDR_LOOPBACK_INIT;
          ^
a.c:8:10: warning: (near initialization for 'b.u') [-Wmissing-braces]


Expected results:
Just as glibc's definition is silent, mingw should add enough {} to allow silent compilation.

Additional info:
Libvirt has had to workaround the problem by using initialization by struct copy, rather than the standardized IP6ADDR_ANY_INIT, because it compiles with -Werror -Wmissing-braces:
http://libvirt.org/git/?p=libvirt.git;a=commitdiff;h=057d26b2ac05dc3d2