Sanitise TGILIBS to use GAP5_LIBS and also removed the duplicate
SEQUTILS_LIBS from GAP5_LIBS.

This fix will also prevent the explicit -L/usr/lib64 -ltcl8.5 link
line on Fedora from capturing a system libstaden-read.so in preference
to the one we attempted to link against.


git-svn-id: svn://svn.code.sf.net/p/staden/code/staden@3674 ba6f2710-ca9f-427c-89d3-5bf716dbc8e1