Add OS_NETBSD macro.

git-svn-id: https://google-glog.googlecode.com/svn/trunk@57 eb4d4688-79bd-11dd-afb4-1d65580434c0

src/utilities.h

@@ -44,6 +44,8 @@
 # define OS_MACOSX
 #elif defined(__FreeBSD__)
 # define OS_FREEBSD
+#elif defined(__NetBSD__)
+# define OS_NETBSD
 #elif defined(__OpenBSD__)
 # define OS_OPENBSD
 #else