Don't include linux-specific headers.

They are unnecessary and plus lead to build failure on non-Linux architectures.

src/conf.h

@@ -23,7 +23,9 @@
 # define CONF_SERVICE_XPATH "//configuration/services/service[@id='%s']/%s"
 # define CONF_USER_MAXLEN 32
 # include <limits.h>
+#ifdef __linux__
 # include <linux/limits.h>
+#endif
 # include <sys/time.h>
 # ifndef PATH_MAX
 #  define PATH_MAX 4096

src/volume.c

@@ -21,7 +21,9 @@
 #include <unistd.h>
 #include <stdlib.h>
 #include <sys/types.h>
+#ifndef __GNU__
 #include <sys/mount.h>
+#endif
 #include "mem.h"
 #include "conf.h"
 #include "log.h"