more robust bound_fixes: external name does appear in "fixes" name space and could clash with direct fixes (e.g. via Subgoal.FOCUS within a global context);
src/Pure
src/FOL
src/HOL
src/ZF
src/CCL
src/CTT
src/Cube
src/FOLP
src/LCF
src/Sequents
src/Doc
src/Tools