diff --git a/Makefile.am b/Makefile.am
index 728e587..3c84c1b 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -6,11 +6,11 @@
 #
 ## Process this file with automake to produce Makefile.in
 if COND_EXPAT
-    SUBDIRS		= expat lib prog
+    SUBDIRS		= lib prog
 else
     SUBDIRS		= lib prog
 endif
-DIST_SUBDIRS		= expat lib prog test
+DIST_SUBDIRS		= lib prog test
 info_TEXINFOS		= udunits2.texi
 udunits2_TEXINFOS	= success.texi failure.texi make.texi
 EXTRA_DIST = \
diff --git a/configure.ac b/configure.ac
index 097f6eb..091e673 100644
--- a/configure.ac
+++ b/configure.ac
@@ -13,7 +13,7 @@ AC_INIT(UDUNITS, 2.1.15, support-udunits@unidata.ucar.edu)
 AC_CONFIG_SRCDIR([lib/converter.c])
 AC_CONFIG_AUX_DIR([.])
 AM_INIT_AUTOMAKE([foreign subdir-objects])
-AC_CONFIG_HEADERS([config.h expat/expat_config.h])
+AC_CONFIG_HEADERS([config.h])
 
 CFLAGS_COVERAGE=''
 LIBS_COVERAGE=''
@@ -37,7 +37,7 @@ AC_ARG_ENABLE([debug],
     CFLAGS="-g${CFLAGS:+ $CFLAGS}"
     debug=true ;;
   no)
-    CFLAGS="-O${CFLAGS:+ $CFLAGS}"
+    CFLAGS="${CFLAGS:+ $CFLAGS}"
     debug=false ;;
   *) AC_MSG_ERROR([bad value ${enableval} for --enable-debug]) ;;
 esac],
@@ -110,20 +110,12 @@ AM_CONDITIONAL([HAVE_CUNIT], [test "$LD_CUNIT"])
 AC_C_CONST
 AC_TYPE_SIZE_T
 
-# Needed for the Expat subpackage:
-AC_C_BIGENDIAN([byteorder=4321], [byteorder=1234])
-AC_DEFINE_UNQUOTED([BYTEORDER], [$byteorder],
-    [Define to 4321 for big-endian and 1234 for little-endian])
-AC_DEFINE([XML_CONTEXT_BYTES], 1024,
-    [How much context to retain around the current parse point.])
-
 # Checks for library functions.
 AC_CHECK_FUNCS([floor memmove memset modf pow strcasecmp strdup strpbrk])
 
 AC_PROG_LIBTOOL
 
 AC_CONFIG_FILES([Makefile
-		 expat/Makefile
                  lib/Makefile
                  lib/xmlFailures/Makefile
                  lib/xmlSuccesses/Makefile