setup: test some header files

The next patch will use "statfs", which requires different header files on
different platforms.

Linux:

    sys/vfs.h or sys/statfs.h

FreeBSD or OSX:

    sys/param.h and sys/mount.h

Therefore test them so we can include the correct ones.

setup.py

@@ -595,6 +595,16 b" for plat, func in [('bsd', 'setproctitle"
     if re.search(plat, sys.platform) and hasfunction(new_compiler(), func):
         osutil_cflags.append('-DHAVE_%s' % func.upper())
 
+for plat, header in [
+    ('bsd|darwin|linux', 'sys/mount.h'),
+    ('bsd|darwin|linux', 'sys/param.h'),
+    ('linux', 'linux/magic.h'),
+    ('linux', 'sys/vfs.h'),
+]:
+    if re.search(plat, sys.platform) and hasheader(new_compiler(), header):
+        macro = header.replace('/', '_').replace('.', '_').upper()
+        osutil_cflags.append('-DHAVE_%s' % macro)
+
 if sys.platform == 'darwin':
     osutil_ldflags += ['-framework', 'ApplicationServices']