[gtk+] Make jasper support optional

[Matthias Clasen <matthiasc src gnome org>]

commit c41e36ad8ae2bdff5323d064d28243c0a40afa8e
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu Jul 16 20:54:42 2009 -0400

    Make jasper support optional
    
    To enable it, one must now pass --with-libjasper to configure.

 README.in    |    3 +++
 configure.in |    8 ++++----
 2 files changed, 7 insertions(+), 4 deletions(-)
---
diff --git a/README.in b/README.in
index 4fb2417..c92639b 100644
--- a/README.in
+++ b/README.in
@@ -34,6 +34,9 @@ Release notes for 2.18
   old custom_widget. Custom_widget does not get destroyed when the
   tooltip goes away.
 
+* JPEG2000 support is no longer enabled by default. It must be
+  explicitly turned on, by passing --with-libjasper to configure.
+
 
 Release notes for 2.16
 ======================
diff --git a/configure.in b/configure.in
index e31eea8..6acbb49 100644
--- a/configure.in
+++ b/configure.in
@@ -825,8 +825,8 @@ AC_ARG_WITH(libtiff,
             [AC_HELP_STRING([--without-libtiff],
                             [disable TIFF loader for gdk-pixbuf])])
 AC_ARG_WITH(libjasper,
-            [AC_HELP_STRING([--without-libjasper],
-                            [disable JPEG2000 loader for gdk-pixbuf])])
+            [AC_HELP_STRING([--with-libjasper],
+                            [enable JPEG2000 loader for gdk-pixbuf])])
 
 AC_ARG_ENABLE(gdiplus,
             [AC_HELP_STRING([--enable-gdiplus],
@@ -941,11 +941,11 @@ dnl Test for libpng
   fi
 
 dnl Test for libjasper
-  if test x$with_libjasper != xno && test -z "$LIBJASPER"; then
+  if test x$with_libjasper = xyes && test -z "$LIBJASPER"; then
     AC_CHECK_LIB(jasper, jas_init, LIBJASPER=-ljasper, [], -ljpeg)
   fi
 
-  if test x$with_libjasper != xno && test -z "$LIBJASPER"; then
+  if test x$with_libjasper = xyes && test -z "$LIBJASPER"; then
      AC_MSG_ERROR([
 *** Checks for JPEG2000 loader failed. You can build without it by passing 
 *** --without-libjasper to configure])