[gnumeric] Protect against pxlib weirdness.

[Jean Bréfort <jbrefort src gnome org>]

commit 7991f3f185f2096241cc47507cf7093ba1841408
Author: Jean Brefort <jean brefort normalesup org>
Date:   Sun Apr 17 11:22:10 2016 +0200

    Protect against pxlib weirdness.

 ChangeLog    |    4 ++++
 configure.ac |    6 +++++-
 2 files changed, 9 insertions(+), 1 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 607cd0f..96aa3ac 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2016-04-17  Jean Brefort  <jean brefort normalesup org>
 
+       * configure.ac: protect against pxlib weirdness.
+
+2016-04-17  Jean Brefort  <jean brefort normalesup org>
+
        * src/graph.c (gnm_go_data_vector_load_len): return a nul length if the
        value is an error.
 
diff --git a/configure.ac b/configure.ac
index cb09b70..abcaba7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -499,7 +499,11 @@ if $try_paradox; then
 fi
 
 if test "x$paradox_msg" = xyes; then
-       enable_paradox=true
+       SAVE_LIBS="$LIBS"
+       LIBS="$LIBS $PARADOX_LIBS"
+       AC_CHECK_FUNC(PX_open_gsf,[ enable_paradox=true ],)
+       LIBS="$SAVE_LIBS"
+       unset SAVE_LIBS
 fi
 AM_CONDITIONAL(WITH_PARADOX, $enable_paradox)
 AC_SUBST(PARADOX_LIBS)