Check for libxmlparse.a using a compile test instead of a link test.

This is much less ambiguous.

configure.in

@@ -17,14 +17,40 @@ AC_CHECK_LIB([gmp], [__gmpz_add], [],
   AC_MSG_FAILURE("Could not find gmp (GNU multi-precision) library"))
 AC_CHECK_LIB([pcre], [pcre_compile], [],
   AC_MSG_FAILURE("Could not find pcre (Perl regular expression) library"))
-AC_CHECK_LIB([xmlparse], [XML_ParserCreate],
-  [AC_DEFINE([HAVE_XMLPARSE], [1], [Support reading Gnucash and XML files])
-   AM_CONDITIONAL(HAVE_XMLPARSE, true)
-   AC_SUBST(LIBS, "-lxmlparse -lxmltok $LIBS")],
-  [AC_MSG_NOTICE([Could not find xmlparse library: Gnucash and XML support disabled])
-   AM_CONDITIONAL(HAVE_XMLPARSE, false)],
-  [-lxmltok])
 
+# check for xmlparse
+AC_ARG_ENABLE(xml,
+  [  --enable-xml            Turn on support for XML parsing],
+  [case "${enableval}" in
+    yes) xml=true ;;
+    no)  xml=false ;;
+    *) AC_MSG_ERROR(bad value ${enableval} for --enable-xml) ;;
+  esac],[xml=true])
+AM_CONDITIONAL(USE_XML, test x$xml = xtrue)
+
+if [test x$xml = xtrue ]; then
+  AC_CACHE_CHECK(
+    [if libxmlparse is available],
+    [libxmlparse_avail],
+    [libxmlparse_save_libs=$LIBS
+     LIBS="-lxmlparse -lxmltok $LIBS"
+     AC_LANG_PUSH(C++)
+     AC_TRY_COMPILE(
+	 [extern "C" {
+	    #include <xmlparse.h>           // expat XML parser
+	  }
+	  class foo {};],
+	 [return 0],
+	 [libxmlparse_avail=true],
+	 [libxmlparse_avail=false])
+     AC_LANG_POP
+     LIBS=$libxmlparse_save_libs])
+  AM_CONDITIONAL(HAVE_XMLPARSE, test x$libxmlparse_avail = xtrue)
+else
+  AM_CONDITIONAL(HAVE_XMLPARSE, false)
+fi
+
+# check for Python
 AC_ARG_ENABLE(python,
   [  --enable-python         Turn on Python support],
   [case "${enableval}" in