libtt: remove hardcoded -lstdc++ used to build TT library

Hardcoding a -lstdc++ is wrong, since not all OSs are likely to handle
C++ in the same way.

The issue is that libtt needs to be built as a C++ library, so we use
a fake dummy.cxx file to convince libtool to do so instead, rather
than trying to force the issue by linking a (possibly missing)
libstdc++.

cde/lib/tt/lib/Makefile.am

@@ -11,10 +11,13 @@ else
 libtt_la_SOURCES =
 endif
 
+# fake things so libtool creates this as a C++ library
+nodist_EXTRA_libtt_la_SOURCES = dummy.cxx
 libtt_la_LIBADD = api/c/libapi.la api/dnd/libdnd.la db/libdb.la mp/libmp.la \
-		  util/libutil.la tttk/libtttk.la -lstdc++
+		  util/libutil.la tttk/libtttk.la
 
 if SOLARIS
+# This stuff should be figured out by configure
 libtt_la_LIBADD += -lnsl -lsocket -lintl -ldl -lc -lw
 endif