--- a/polyorb-config.in
+++ b/polyorb-config.in
@@ -29,12 +29,7 @@
       exec_prefix=`cygpath -w $exec_prefix`
 esac
 
-if [ -f "${exec_prefix}"/include/polyorb/polyorb.ads ]; then
-  prefix="${exec_prefix}"
-else
-  # Fall back to configure-time prefix
-  prefix="@prefix@"
-fi
+prefix="/usr"
 
 have_gnatmake_aPdir=@HAVE_GNATMAKE_APDIR@
 default_appli="@APPLI_LIST@"
@@ -184,10 +179,10 @@
 done
 
 exec_prefix="@exec_prefix@"
-includedir="@includedir@"
-libdir="@libdir@"
+includedir="/usr/share/ada/adainclude"
+libdir="/usr/lib/ada/adalib"
 polyorb_dir="${includedir}/polyorb"
-polyorb_lib="@LDFLAGS@ -L${libdir}/polyorb/static"
+polyorb_lib="@LDFLAGS@ -L/usr/lib"
 corba_idl_dir="-I${includedir}/polyorb"
 
 for P in $appli; do
@@ -262,7 +257,7 @@
 fi
 
 if test x$have_gnatmake_aPdir = xyes; then
-  apdir="-aP${prefix}/lib/gnat"
+  apdir="-aP/usr/share/ada/adainclude"
 fi
 
 if test ! x"$echo_prefix" = x"true"  -a ! x"$echo_exec_prefix" = x"true" -a ! x"$echo_cflags" = x"true" -a ! x"$echo_libs" = x"true" -a ! x"$echo_idls" = x"true"; then