build: Disable unused run-time type information for dselect

The dselect codebase does not make use of RTTI (run-time type
information), so including support for it is a waste.

debian/changelog

@@ -6,6 +6,7 @@ dpkg (1.17.14) UNRELEASED; urgency=low
   * Switch debian/copyright to machine-readable format 1.0, and extensively
     update the information within.
   * Bump Standards-Version to 3.9.6 (no changes needed).
+  * Disable unused run-time type information for dselect.
 
   [ Raphaël Hertzog ]
   * Explain better in deb-triggers(5) why interest/activate-noawait should be

dselect/Makefile.am

@@ -13,6 +13,8 @@ AM_CPPFLAGS = \
 	-iquote $(builddir) \
 	-I$(top_builddir) \
 	-I$(top_srcdir)/lib
+AM_CXXFLAGS = \
+	-fno-rtti
 
 
 bin_PROGRAMS = dselect