use os_bsd and OS_BSD and add some OS_FREEBSD conditions

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 6d530445bd8cd78ab0cc4b7e338002d3aa0d70c0..e72fa51aef9b472113bfd6f2eeda6917481e0d4d 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -1211,15 +1211,15 @@
               '-Wsign-compare',
             ]
           }],
-          [ 'os_posix==1 and OS!="mac" and OS!="openbsd" and OS!="android" and chromeos==0', {
+          [ 'os_posix==1 and os_bsd!=1 and OS!="mac" and OS!="android" and chromeos==0', {
             'cflags': [
               # Don't warn about ignoring the return value from e.g. close().
               # This is off by default in some gccs but on by default in others.
               # Currently this option is not set for Chrome OS build because
               # the current version of gcc (4.3.4) used for building Chrome in
               # Chrome OS chroot doesn't support this option.
-              # OpenBSD does not support this option either, since it's using
-              # gcc 4.2.1, which does not have this flag yet.
+              # BSD systems do not support this option either, since they are
+              # usually using gcc 4.2.1, which does not have this flag yet.
               # TODO(mazda): remove the conditional for Chrome OS when gcc
               # version is upgraded.
               '-Wno-unused-result',
@@ -1284,7 +1284,7 @@
               ['exclude', '(^|/)gtk_[^/]*\\.(h|cc)$'],
             ],
           }],
-          ['OS!="linux" and OS!="openbsd"', {
+          ['OS!="linux" and OS!="openbsd" and OS!="freebsd"', {
             'sources/': [
               ['exclude', '_xdg(_unittest)?\\.(h|cc)$'],
             ],
@@ -1296,10 +1296,10 @@
               ['exclude', '(^|/)(wayland)_[^/]*\\.(h|cc)$'],
             ],
           }],
-          # Do not exclude the linux files on OpenBSD since most of them can be
+          # Do not exclude the linux files on *BSD since most of them can be
           # shared at this point.
           # In case a file is not needed, it is going to be excluded later on.
-          ['OS!="linux" and OS!="openbsd"', {
+          ['OS!="linux" and OS!="openbsd" and OS!="freebsd"', {
             'sources/': [
               ['exclude', '_linux(_unittest)?\\.(h|cc)$'],
               ['exclude', '(^|/)linux/'],