migrate fully to meson build system

- drop old build system
- move shared include and source files to common directory
- drop "rc-" prefix from shared include and source files
- move executable-specific code to individual directories under src
- adjust top-level .gitignore file for new build system

This closes #489.

src/swclock/meson.build

@@ -0,0 +1,7 @@
+executable('swclock',
+  ['swclock.c', misc_c, usage_c, version_h],
+  c_args : cc_branding_flags,
+  include_directories: [incdir, einfo_incdir, rc_incdir],
+  link_with: [libeinfo,librc],
+  install: true,
+  install_dir: rc_sbindir)

src/swclock/swclock.c

@@ -0,0 +1,106 @@
+/*
+ * swclock.c
+ * Sets the system time from the mtime of the given file.
+ * This is useful for systems who do not have a working RTC and rely on ntp.
+ * OpenRC relies on the correct system time for a lot of operations
+ * so this is needed quite early.
+ */
+
+/*
+ * Copyright (c) 2007-2015 The OpenRC Authors.
+ * See the Authors file at the top-level directory of this distribution and
+ * https://github.com/OpenRC/openrc/blob/HEAD/AUTHORS
+ *
+ * This file is part of OpenRC. It is subject to the license terms in
+ * the LICENSE file found in the top-level directory of this
+ * distribution and at https://github.com/OpenRC/openrc/blob/HEAD/LICENSE
+ * This file may not be copied, modified, propagated, or distributed
+ *    except according to the terms contained in the LICENSE file.
+ */
+
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <utime.h>
+
+#include "einfo.h"
+#include "rc.h"
+#include "misc.h"
+#include "_usage.h"
+
+#define RC_SHUTDOWNTIME    RC_SVCDIR "/shutdowntime"
+
+const char *applet = NULL;
+const char *extraopts = "file";
+const char getoptstring[] = "sw" getoptstring_COMMON;
+const struct option longopts[] = {
+	{ "save", 0, NULL, 's' },
+	{ "warn", 0, NULL, 'w' },
+	longopts_COMMON
+};
+const char * const longopts_help[] = {
+	"saves the time",
+	"no error if no reference file",
+	longopts_help_COMMON
+};
+const char *usagestring = NULL;
+
+int main(int argc, char **argv)
+{
+	int opt, sflag = 0, wflag = 0;
+	const char *file = RC_SHUTDOWNTIME;
+	struct stat sb;
+	struct timeval tv;
+
+	applet = basename_c(argv[0]);
+	while ((opt = getopt_long(argc, argv, getoptstring,
+		    longopts, (int *) 0)) != -1)
+	{
+		switch (opt) {
+		case 's':
+			sflag = 1;
+			break;
+		case 'w':
+			wflag = 1;
+			break;
+		case_RC_COMMON_GETOPT
+		}
+	}
+
+	if (optind < argc)
+		file = argv[optind++];
+
+	if (sflag) {
+		if (stat(file, &sb) == -1) {
+			opt = open(file, O_WRONLY | O_CREAT, 0644);
+			if (opt == -1)
+				eerrorx("swclock: open: %s", strerror(errno));
+			close(opt);
+		} else
+			if (utime(file, NULL) == -1)
+				eerrorx("swclock: utime: %s", strerror(errno));
+		return 0;
+	}
+
+	if (stat(file, &sb) == -1) {
+		if (wflag != 0 && errno == ENOENT)
+			ewarn("swclock: `%s': %s", file, strerror(errno));
+		else
+			eerrorx("swclock: `%s': %s", file, strerror(errno));
+		return 0;
+	}
+
+	tv.tv_sec = sb.st_mtime;
+	tv.tv_usec = 0;
+
+	if (settimeofday(&tv, NULL) == -1)
+		eerrorx("swclock: settimeofday: %s", strerror(errno));
+
+	return 0;
+}