Changes to build/ from a combination of FreeBSD and OpenBSD patches.

build/build_config.h

Index: build/build_config.h
diff --git a/build/build_config.h b/build/build_config.h
index 8b74e500fe06042ebb0dabba9c37e2d9c73f6da8..fbb2eefc351d1b3b843c8cb7167a907814825529 100644
--- a/build/build_config.h
+++ b/build/build_config.h
@@ -29,10 +29,18 @@
 #elif defined(__FreeBSD__)
 #define OS_FREEBSD 1
 #define TOOLKIT_GTK
+#elif defined(__OpenBSD__)
+#define OS_OPENBSD 1
+#define TOOLKIT_GTK
 #else
 #error Please add support for your platform in build/build_config.h
 #endif
 
+#if defined(OS_LINUX) || defined(OS_FREEBSD) || defined(OS_OPENBSD)
+#define USE_NSS 1  // Use NSS for crypto.
+#define USE_X11 1  // Use X for graphics.
+#endif
+
 // For access to standard POSIXish features, use OS_POSIX instead of a
 // more specific macro.
 #if defined(OS_MACOSX) || defined(OS_LINUX) || defined(OS_FREEBSD)
@@ -44,16 +52,6 @@
 #define USE_BASE_DATA_PACK 1
 #endif
 
-// Use NSS for crypto.
-#if defined(OS_LINUX) || defined(OS_FREEBSD)
-#define USE_NSS 1
-#endif
-
-// Use X11 (and hence GTK/GDK)
-#if defined(OS_LINUX) || defined(OS_FREEBSD)
-#define USE_X11 1
-#endif
-
 // Use tcmalloc
 #if defined(OS_WIN) && ! defined(NO_TCMALLOC)
 #define USE_TCMALLOC 1