--- a/scripts/defs.mak.in
+++ b/scripts/defs.mak.in
@@ -12,6 +12,7 @@
 exec_prefix = @exec_prefix@
 bindir = @bindir@
 libdir = @libdir@
+datadir = @datadir@
 mandir = @mandir@
 
 VERSION                = @VERSION@
@@ -33,9 +34,9 @@
 LIBDIR                 = ${libdir}
 DOCDIR                 = ${libdir}/irsim/doc
 SYSDIR                 = ${libdir}/irsim/sys
-PRMDIR                 = ${libdir}/irsim/prm
-TCLDIR                 = ${libdir}/irsim/tcl
-XBMDIR                 = ${libdir}/irsim/tcl/bitmaps
+PRMDIR                 = ${datadir}/irsim/prm
+TCLDIR                 = ${libdir}/irsim/tcl
+XBMDIR                 = ${libdir}/irsim/tcl/bitmaps
 
 MAIN_EXTRA_LIBS	       = @extra_libs@
 LD_EXTRA_LIBS	       = @ld_extra_libs@