diff --git a/distrib/configure.ac.in b/distrib/configure.ac.in
--- a/distrib/configure.ac.in
+++ b/distrib/configure.ac.in
@@ -12,8 +12,15 @@
 
 FP_GMP
 
+dnl Various things from the source distribution configure
 bootstrap_target=@TargetPlatform@
 
+FFIIncludeDir=@FFIIncludeDir@
+FFILibDir=@FFILibDir@
+AC_SUBST(FFILibDir)
+AC_SUBST(FFIIncludeDir)
+
+
 # We have to run these unconditionally as FPTOOLS_SET_PLATFORM_VARS wants the
 # values it computes.
 AC_CANONICAL_BUILD