Linking with -lc not a good idea

I noticed that pltcl.so is now always linked with -lc.  That is normally not a 
good idea with gcc, because gcc figures out its own order of -lgcc and -lc.  
If you specify -lc explicitly, then you override -lgcc.

I think this change

http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/pl/tcl/
Makefile.diff?r1=1.39&r2=1.40

needs to be reconsidered.