hack/libdm_installed: Add a test for libdevmapper.h

Avoid crashing 'make' with:

  No package 'devmapper' found

by disabling the devmapper driver when the library it requires is not
installed.  Also give the libdm_no_deferred_remove script a more
specific name to avoid confusion.

Signed-off-by: W. Trevor King <wking@tremily.us>

Makefile

@@ -11,7 +11,7 @@ LIBEXECDIR ?= ${PREFIX}/libexec
 MANDIR ?= ${PREFIX}/share/man
 ETCDIR ?= ${DESTDIR}/etc
 ETCDIR_CRIO ?= ${ETCDIR}/crio
-BUILDTAGS ?= seccomp $(shell hack/btrfs_tag.sh) $(shell hack/libdm_tag.sh) $(shell hack/btrfs_installed_tag.sh) $(shell hack/ostree_tag.sh) $(shell hack/selinux_tag.sh)
+BUILDTAGS ?= seccomp $(shell hack/btrfs_tag.sh) $(shell hack/libdm_installed.sh) $(shell hack/libdm_no_deferred_remove_tag.sh) $(shell hack/btrfs_installed_tag.sh) $(shell hack/ostree_tag.sh) $(shell hack/selinux_tag.sh)
 CRICTL_CONFIG_DIR=${DESTDIR}/etc
 
 BASHINSTALLDIR=${PREFIX}/share/bash-completion/completions

hack/libdm_installed.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+cc -E - > /dev/null 2> /dev/null << EOF
+#include <libdevmapper.h>
+EOF
+if test $? -ne 0 ; then
+	echo exclude_graphdriver_devicemapper
+fi