Remove libltdl, similarly to what has been done on PulseAudio.

Get rid of the internal copy of libltdl and instead use the system copy,
requiring that to be available. It does not make sense to duplicate this
further, and it's especially a bad idea to use an internal older copy of
the library for distributors and final users.

4 files changed, 27 insertions, 7 deletions

diff --git a/Makefile.am b/Makefile.am
index 507a02f..802daf0 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -19,7 +19,7 @@
 dist_doc_DATA = README
 
 EXTRA_DIST = bootstrap.sh autogen.sh LGPL libcanberra.schemas
-SUBDIRS = libltdl src gtkdoc doc
+SUBDIRS = src gtkdoc doc
 
 MAINTAINERCLEANFILES = README
 noinst_DATA = README
diff --git a/bootstrap.sh b/bootstrap.sh
index ce5d7e4..29d356f 100755
--- a/bootstrap.sh
+++ b/bootstrap.sh
@@ -63,7 +63,7 @@ else
 
     mkdir -p m4
     gtkdocize --copy --flavour no-tmpl --docdir gtkdoc
-    "$LIBTOOLIZE" -c --force --ltdl --recursive
+    "$LIBTOOLIZE" -c --force --recursive
     run_versioned aclocal "$VERSION" -I m4
     run_versioned autoconf 2.63 -Wall
     run_versioned autoheader 2.63
diff --git a/configure.ac b/configure.ac
index 79c05b8..51dc305 100644
--- a/configure.ac
+++ b/configure.ac
@@ -65,9 +65,32 @@ done
 
 #### libtool stuff ####
 LT_PREREQ(2.2)
-LT_CONFIG_LTDL_DIR([libltdl])
 LT_INIT([dlopen win32-dll disable-static])
-LTDL_INIT([convenience recursive])
+
+dnl Unfortunately, even up to libtool 2.2.6a there is no way to know
+dnl exactly which version of libltdl is present in the system, so we
+dnl just assume that it's a working version as long as we have the
+dnl library and the header files.
+dnl
+dnl As an extra safety device, check for lt_dladvise_init() which is
+dnl only implemented in libtool 2.x, and refine as we go if we have
+dnl refined requirements.
+dnl
+dnl Check the header files first since the system may have a
+dnl libltdl.so for runtime, but no headers, and we want to bail out as
+dnl soon as possible.
+dnl
+dnl We don't need any special variable for this though, since the user
+dnl can give the proper place to find libltdl through the standard
+dnl variables like LDFLAGS and CPPFLAGS.
+
+AC_CHECK_HEADER([ltdl.h],
+    [AC_CHECK_LIB([ltdl], [lt_dladvise_init], [LIBLTDL=-lltdl], [LIBLTDL=])],
+    [LIBLTDL=])
+
+AS_IF([test "x$LIBLTDL" = "x"],
+    [AC_MSG_ERROR([Unable to find libltdl.])])
+AC_SUBST([LIBLTDL])
 
 #### Determine build environment ####
 
@@ -552,7 +575,6 @@ GTK_DOC_CHECK(1.9)
 
 AC_CONFIG_FILES([
 Makefile
-libltdl/Makefile
 src/Makefile
 libcanberra.pc
 libcanberra-gtk.pc
diff --git a/src/Makefile.am b/src/Makefile.am
index d1b4d89..1fb5168 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -85,8 +85,6 @@ if BUILTIN_DSO
 libcanberra_la_SOURCES += \
 	dso.c \
 	driver-order.c driver-order.h
-libcanberra_la_CFLAGS += \
-	$(LTDLINCL)
 libcanberra_la_LIBADD += \
 	$(LIBLTDL)