Link to libglib, use it in one place to start

libglib is a hard requirement of other projects on the host, such
as libostree.  Let's make use of it, since it has a lot of useful
functionality for C programs.

Specifically, it aborts on OOM by default (because in practice anything that
isn't the kernel/pid 1 isn't going to be able to continue), so we can just use
`g_strdup()`.

(Note that it's required nowadays that `g_malloc() = malloc()`, so it's
 OK that we're passing this to `free()`.)

Makefile.am

@@ -10,10 +10,10 @@ oci_umount_jsondir=/usr/share/containers/oci/hooks.d
 oci_umount_options_DATA = oci-umount-options.conf
 oci_umount_optionsdir=/usr/share/oci-umount/
 
-oci_umount_CFLAGS = -Wall -Wextra -std=c99 $(YAJL_CFLAGS)
+oci_umount_CFLAGS = -Wall -Wextra -std=c99
 oci_umount_LDADD = $(YAJL_LIBS)
-oci_umount_CFLAGS += $(SELINUX_CFLAGS)
-oci_umount_LDADD += $(SELINUX_LIBS)
+oci_umount_CFLAGS += $(SELINUX_CFLAGS) $(GLIB_CFLAGS)
+oci_umount_LDADD += $(SELINUX_LIBS) $(GLIB_LIBS)
 
 dist_man_MANS = oci-umount.1
 EXTRA_DIST = README.md LICENSE

configure.ac

@@ -7,6 +7,7 @@ AM_PROG_CC_C_O
 AC_USE_SYSTEM_EXTENSIONS
 AC_SYS_LARGEFILE
 
+PKG_CHECK_MODULES([GLIB], [gio-unix-2.0 >= 2.50])
 PKG_CHECK_MODULES([YAJL], [yajl >= 2.0.0])
 PKG_CHECK_MODULES([SELINUX], [libselinux >= 2.0.0])
 PKG_CHECK_MODULES([LIBMOUNT], [mount >= 2.23.0])

src/oci-umount.c

@@ -1,4 +1,5 @@
 #define _GNU_SOURCE
+#include <glib.h>
 #include <stdio.h>
 #include <libgen.h>
 #include <stdlib.h>
@@ -363,11 +364,7 @@ static int map_mount_host_to_container(const char *id, const struct config_mount
 	int ret;
 	unsigned nr_mapped = 0;
 
-	host_mnt_dup = strdup(host_mnt);
-	if (!host_mnt_dup) {
-		pr_perror("%s: strdup(%s) failed.", id, host_mnt);
-		return -1;
-	}
+	host_mnt_dup = g_strdup(host_mnt);
 
 	str = host_mnt_dup;
 	do {