diff --git a/configure.in b/configure.in
index 3fd2c13f105c48880e16abe057f1ead668a09d2c..28fc79aa3a0b683e31e53b63eb2e98ff9b8ce25c 100644
--- a/configure.in
+++ b/configure.in
@@ -1,4 +1,4 @@
-dnl $Id: configure.in,v 1.102 2006-08-26 13:34:43 geuzaine Exp $
+dnl $Id: configure.in,v 1.103 2006-09-30 02:38:04 guzik Exp $
 dnl
 dnl Copyright (C) 1997-2006 C. Geuzaine, J.-F. Remacle
 dnl
@@ -53,6 +53,10 @@ AC_ARG_WITH(osmesa-prefix,
             AC_HELP_STRING([--with-osmesa-prefix=PFX],
                            [prefix where OSMesa is installed]),
             [OSMESA_PREFIX=$withval])
+AC_ARG_WITH(cgns-prefix,
+            AC_HELP_STRING([--with-cgns-prefix=PFX],
+                           [prefix where CGNS is installed]),
+            [CGNS_PREFIX=$withval])
 
 dnl Parse '--enable' command line options
 AC_ARG_ENABLE(gsl,
@@ -100,6 +104,9 @@ AC_ARG_ENABLE(matheval,
 AC_ARG_ENABLE(osmesa,
               AC_HELP_STRING([--enable-osmesa],
                              [use OSMesa for offscreen rendering (default=no)]))
+AC_ARG_ENABLE(cgns,
+              AC_HELP_STRING([--enable-cgns],
+                             [enable CGNS output (default=no)]))
 
 dnl Get the operating system name
 UNAME=`uname`
@@ -513,6 +520,25 @@ if test "x${GSL}" != "xyes"; then
   fi
 fi
 
+dnl Check for CGNS
+if test "x${CGNS_PREFIX}" != "x"; then
+  enable_cgns="yes"
+fi
+if test "x$enable_cgns" = "xyes"; then
+  if test "x${CGNS_PREFIX}" != "x"; then
+    LDFLAGS="-L${CGNS_PREFIX}/lib ${LDFLAGS}"
+  fi
+  AC_CHECK_LIB(cgns,main,CGNS="yes",CGNS="no")
+  if test "x${CGNS}" = "xyes"; then
+    if test "x${CGNS_PREFIX}" = "x"; then
+      GMSH_LIBS="${GMSH_LIBS} -lcgns"
+    else
+      GMSH_LIBS="${GMSH_LIBS} -L${CGNS_PREFIX}/lib -lcgns"
+      FLAGS="${FLAGS} -DHAVE_LIBCGNS -I${CGNS_PREFIX}/include"
+    fi
+  fi
+fi
+
 dnl Check if we should build the parallel version
 if test "x$enable_parallel" = "xyes"; then
   FLAGS="-DHAVE_PARALLEL ${FLAGS}"
@@ -581,6 +607,16 @@ case "$UNAME" in
 
 esac
 
+dnl Compiler characteristics
+dnl Check sizeof size_t (flag as 64 if not 32)
+AC_CHECK_SIZEOF([size_t])
+if test $ac_cv_sizeof_size_t != 4; then
+  FLAGS="$FLAGS -DHAVE_64BIT_SIZE_T"
+  if test $ac_cv_sizeof_size_t != 8; then
+    AC_MSG_WARN([Unsupported size of size_t - this may affect FNV hashing.])
+  fi
+fi
+
 dnl Write output
 AC_SUBST(UNAME)
 AC_SUBST(FLAGS)