switchroot: Move `path_is_on_readonly_fs` to header file

This simplifies the build system by removing the need for
`libswitchroot-mountutil.la`.

Original idea by @cgwalters in #477.

Closes: #478
Approved by: cgwalters

Makefile-switchroot.am

@@ -16,19 +16,10 @@
 # Boston, MA 02111-1307, USA.
 
 if BUILDOPT_SYSTEMD
-
 ostree_boot_PROGRAMS += ostree-remount
-
-noinst_LTLIBRARIES += libswitchroot-mountutil.la
 endif
 
-libswitchroot_mountutil_la_SOURCES = \
-	src/switchroot/ostree-mount-util.c \
-	src/switchroot/ostree-mount-util.h \
-	$(NULL)
-
 ostree_prepare_root_SOURCES = \
-    src/switchroot/ostree-mount-util.c \
     src/switchroot/ostree-mount-util.h \
     src/switchroot/ostree-prepare-root.c \
     $(NULL)
@@ -54,6 +45,8 @@ ostree_boot_PROGRAMS += ostree-prepare-root
 ostree_prepare_root_CFLAGS = $(AM_CFLAGS) -Isrc/switchroot
 endif
 
-ostree_remount_SOURCES = src/switchroot/ostree-remount.c
+ostree_remount_SOURCES = \
-ostree_remount_LDADD = libswitchroot-mountutil.la
+    src/switchroot/ostree-mount-util.h \
+    src/switchroot/ostree-remount.c \
+    $(NULL)
 ostree_remount_CFLAGS = $(AM_CFLAGS) -Isrc/switchroot

src/switchroot/ostree-mount-util.c

@@ -1,40 +0,0 @@
-/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
- *
- * Copyright (C) 2011,2013 Colin Walters <walters@verbum.org>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 02111-1307, USA.
- *
- * Author: Colin Walters <walters@verbum.org>
- */
-
-#include "config.h"
-
-#include <err.h>
-#include <stdlib.h>
-#include <sys/statvfs.h>
-
-#include "ostree-mount-util.h"
-
-int
-path_is_on_readonly_fs (char *path)
-{
-  struct statvfs stvfsbuf;
-
-  if (statvfs (path, &stvfsbuf) == -1)
-    err (EXIT_FAILURE, "statvfs(%s)", path);
-
-  return (stvfsbuf.f_flag & ST_RDONLY) != 0;
-}

src/switchroot/ostree-mount-util.h

@@ -19,6 +19,22 @@
  *
  */
 
-#pragma once
+#ifndef __OSTREE_MOUNT_UTIL_H_
+#define __OSTREE_MOUNT_UTIL_H_
 
-int path_is_on_readonly_fs (char *path);
+#include <err.h>
+#include <stdlib.h>
+#include <sys/statvfs.h>
+
+static inline int
+path_is_on_readonly_fs (char *path)
+{
+  struct statvfs stvfsbuf;
+
+  if (statvfs (path, &stvfsbuf) == -1)
+    err (EXIT_FAILURE, "statvfs(%s)", path);
+
+  return (stvfsbuf.f_flag & ST_RDONLY) != 0;
+}
+
+#endif /* __OSTREE_MOUNT_UTIL_H_ */