network: fix compile error

BUILD SUCCESSFUL

Total time: 35.396 secs
make -r -C build/release/ all
make[1]: Entering directory `/home/zwu/osv/build/release'
  CXX loader.o
  CXX runtime.o
  CXX drivers/vga.o
  CXX bsd/net.o
  CXX bsd/porting/networking.o
/home/zwu/osv/bsd/porting/networking.cc: In function ‘int osv::if_set_mtu(std::string, u16)’:
/home/zwu/osv/bsd/porting/networking.cc:43:32: error: missing braces around initializer for ‘char [16]’ [-Werror=missing-braces]
cc1plus: all warnings being treated as errors
make[1]: *** [bsd/porting/networking.o] Error 1
make[1]: Leaving directory `/home/zwu/osv/build/release'
make: *** [all] Error 2

Signed-off-by: Zhi Yong Wu <zwu.kernel@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

bsd/porting/networking.cc

@@ -36,11 +36,13 @@ void for_each_if(std::function<void (std::string)> func)
 
 int if_set_mtu(std::string if_name, u16 mtu)
 {
+    struct bsd_ifreq ifreq;
+
     if (if_name.empty()) {
         return (EINVAL);
     }
 
-    struct bsd_ifreq ifreq = {0};
+    bzero(&ifreq, sizeof(struct bsd_ifreq));
 
     /* IF Name */
     strncpy(ifreq.ifr_name, if_name.c_str(), IFNAMSIZ);