Index: configure.ac
===================================================================
--- configure.ac	(revision 7534)
+++ configure.ac	(working copy)
@@ -1,9 +1,9 @@
 # Process this file with autoconf to produce a configure script.
-AC_PREREQ(2.57)
+AC_PREREQ(2.61)
 AC_INIT([libextractor], [0.5.20c], [bug-libextractor@gnu.org])
-AC_REVISION($Revision: 1.67 $)
 AM_INIT_AUTOMAKE([libextractor], [0.5.20c])
-AM_CONFIG_HEADER(config.h)
+AC_CONFIG_HEADERS([config.h])
+AH_TOP([#define _GNU_SOURCE  1])
 
 LIB_VERSION_CURRENT=2
 LIB_VERSION_REVISION=1
@@ -12,8 +12,6 @@
 AC_SUBST(LIB_VERSION_REVISION)
 AC_SUBST(LIB_VERSION_AGE)
 
-AH_TOP([#define _GNU_SOURCE  1])
-
 # Checks for programs.
 AC_CANONICAL_HOST
 AC_USE_SYSTEM_EXTENSIONS
@@ -22,7 +20,6 @@
 AC_PROG_CPP
 AC_PROG_CXX
 AC_CHECK_PROG(HAVE_CXX, $CXX, yes, no)
-AM_CONDITIONAL(HAVE_CXX, test "x$HAVE_CXX" = "xyes")
 AC_PROG_INSTALL
 AC_PROG_LN_S
 AC_PROG_MAKE_SET
@@ -33,7 +30,6 @@
 AC_PROG_LIBTOOL
 AC_LIB_LTDL
 m4_ifdef([_AC_SEEN_TAG(libltdl)], [], [AC_CONFIG_SUBDIRS(libltdl)])
-AC_CANONICAL_HOST
 AC_SUBST(LTDLINCL)
 AC_SUBST(LIBLTDL)
 AC_SUBST(MKDIR_P)
@@ -152,6 +148,9 @@
  CFLAGS="-fno-strict-aliasing $CFLAGS"
 fi
 
+AM_CONDITIONAL(HAVE_CXX, test "x$HAVE_CXX" = "xyes")
+
+
 # Checks for libraries.
 
 # the library tests that follow should not result in every plugin linking to them,
@@ -169,13 +168,18 @@
 # test if we have vorbisfile
 # prior versions had ov_open_callbacks in libvorbis, test that, too.
 AC_CHECK_LIB(vorbisfile, ov_open_callbacks,
-        [AM_CONDITIONAL(HAVE_VORBISFILE, true)
-         AC_DEFINE(HAVE_VORBISFILE,1,[Have vorbisfile])],
-        [AM_CONDITIONAL(HAVE_VORBISFILE, false)],
+        [AC_CHECK_HEADERS([vorbis/vorbisfile.h],
+         [AM_CONDITIONAL(HAVE_VORBISFILE, true)
+          AC_DEFINE(HAVE_VORBISFILE,1,[Have vorbisfile])],
+         [AM_CONDITIONAL(HAVE_VORBISFILE, false)
+          AC_DEFINE(HAVE_VORBISFILE,0,[lacking vorbisfile])]),
+        [AM_CONDITIONAL(HAVE_VORBISFILE, false)]],
         -lvorbis -logg)
 AC_CHECK_LIB(FLAC, FLAC__stream_decoder_init_stream,
-        [AM_CONDITIONAL(HAVE_FLAC, true)
-         AC_DEFINE(HAVE_FLAC,1,[Have flac])],
+        [AC_CHECK_HEADERS([FLAC/all.h],
+         [AM_CONDITIONAL(HAVE_FLAC, true)
+          AC_DEFINE(HAVE_FLAC,1,[Have flac])],
+         AM_CONDITIONAL(HAVE_FLAC, false))],
         [AM_CONDITIONAL(HAVE_FLAC, false)],
         -logg)
 # test without -logg to see whether we really need it (libflac can be without)
@@ -190,23 +194,31 @@
         -logg)
 
 AC_CHECK_LIB(z, inflate,
-        [AM_CONDITIONAL(HAVE_ZLIB, true)
-        AC_DEFINE(HAVE_ZLIB,1,[Have zlib])],
+        [AC_CHECK_HEADERS([zlib.h],
+         [AM_CONDITIONAL(HAVE_ZLIB, true)
+          AC_DEFINE(HAVE_ZLIB,1,[Have zlib])],
+         AM_CONDITIONAL(HAVE_ZLIB, false))],
         [AM_CONDITIONAL(HAVE_ZLIB, false)])
 
 AC_CHECK_LIB(rpm, rpmReadPackageFile,
-        [AM_CONDITIONAL(HAVE_LIBRPM, true)
-        AC_DEFINE(HAVE_LIBRPM,1,[Have librpm])],
+        [AC_CHECK_HEADERS([rpm/rpmlib.h rpm/rpmts.h],
+         [AM_CONDITIONAL(HAVE_LIBRPM, true)
+          AC_DEFINE(HAVE_LIBRPM,1,[Have librpm])],
+         AM_CONDITIONAL(HAVE_LIBRPM, false))],
         [AM_CONDITIONAL(HAVE_LIBRPM, false)])
 
 AC_CHECK_LIB(bz2, BZ2_decompress,
-        [AM_CONDITIONAL(HAVE_BZ2, true)
-        AC_DEFINE(HAVE_LIBBZ2,1,[Have libbz2])],
+        [AC_CHECK_HEADERS([bzlib.h],
+         [AM_CONDITIONAL(HAVE_BZ2, true)
+          AC_DEFINE(HAVE_LIBBZ2,1,[Have libbz2])],
+         AM_CONDITIONAL(HAVE_BZ2, false))],
         [AM_CONDITIONAL(HAVE_BZ2, false)])
 
 AC_CHECK_LIB(mpeg2, mpeg2_init,
-        [AM_CONDITIONAL(HAVE_MPEG2, true)
-        AC_DEFINE(HAVE_MPEG2,1,[Have libmpeg2])],
+        [AC_CHECK_HEADERS([mpeg2dec/mpeg2.h],
+          [AM_CONDITIONAL(HAVE_MPEG2, true)
+           AC_DEFINE(HAVE_MPEG2,1,[Have libmpeg2])],
+         AM_CONDITIONAL(HAVE_MPEG2, false))],
         [AM_CONDITIONAL(HAVE_MPEG2, false)])
 
 # restore LIBS
@@ -232,14 +244,8 @@
 AC_HEADER_STDC
 AC_HEADER_DIRENT
 AC_HEADER_STDBOOL
-AC_CHECK_HEADERS([fcntl.h netinet/in.h stdlib.h string.h unistd.h libintl.h limits.h stddef.h zlib.h])
-AC_CHECK_HEADERS([ltdl.h iconv.h bzlib.h mpeg2dec/mpeg2.h])
-# fixme, we need to die here if a header is not found!
+AC_CHECK_HEADERS([ltdl.h iconv.h fcntl.h netinet/in.h stdlib.h string.h unistd.h libintl.h limits.h stddef.h zlib.h])
 
-AC_CHECK_HEADERS([vorbis/vorbisfile.h])
-
-AC_CHECK_HEADERS([FLAC/all.h])
-
 # Checks for typedefs, structures, and compiler characteristics.
 AC_C_CONST
 AC_C_INLINE
Index: doc/version.texi
===================================================================
--- doc/version.texi	(revision 7534)
+++ doc/version.texi	(working copy)
@@ -1,4 +1,4 @@
-@set UPDATED 23 June 2008
-@set UPDATED-MONTH June 2008
+@set UPDATED 23 July 2008
+@set UPDATED-MONTH July 2008
 @set EDITION 0.5.20c
 @set VERSION 0.5.20c
Index: acinclude.m4
===================================================================
--- acinclude.m4	(revision 7534)
+++ acinclude.m4	(working copy)
@@ -1,5 +1,3 @@
-AC_PREREQ(2.52)
-
 define(GNUPG_CHECK_ENDIAN,
   [ if test "$cross_compiling" = yes; then
         AC_MSG_WARN(cross compiling; assuming big endianess)