define OS_BSD on *BSD and replace the ifdefs to use that

build/build_config.h

Index: build/build_config.h
diff --git a/build/build_config.h b/build/build_config.h
index 3dc75d616b1ddf8d664cb21f70468ae33941213c..97b0b5aa93cf22830ba1ee5f7cfb3a2aa6d2901f 100644
--- a/build/build_config.h
+++ b/build/build_config.h
@@ -43,15 +43,16 @@
 #error Please add support for your platform in build/build_config.h
 #endif
 
-#if defined(OS_LINUX) || defined(OS_FREEBSD) || defined(OS_OPENBSD) || \
-    defined(OS_SOLARIS)
-#define USE_X11 1  // Use X for graphics.
-#endif
-
 #if defined(USE_OPENSSL) && defined(USE_NSS)
 #error Cannot use both OpenSSL and NSS
 #endif
 
+// For access to standard BSD features, use OS_BSD instead of a
+// more specific macro.
+#if defined(OS_FREEBSD) || defined(OS_OPENBSD)
+#define OS_BSD 1
+#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) ||     \
@@ -60,6 +61,11 @@
 #define OS_POSIX 1
 #endif
 
+#if defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_ANDROID) && \
+    !defined(OS_NACL)
+#define USE_X11 1  // Use X for graphics.
+#endif
+
 // Use tcmalloc
 #if (defined(OS_WIN) || defined(OS_LINUX)) && !defined(NO_TCMALLOC)
 #define USE_TCMALLOC 1