Survey CLTL2 files

[masinter]

I finally took the time to look more closely at the files in the CLTL2 directory, using CSBROWSER to compare 'sources' to 'CLTL2' to 'sources' and also to the oldest version in GitHub medley repo and older versions.

• [ ] ADISPLAY: the old ADISPLAY from lispcore/sources is 1994 while ADISPLAY from CLTL2 is older (1993). Puzzle is why this is in CLTL2
• [ ] ADVISE - changes to XCL:(RE/UN//)ADVISE-FUNCTION with executables?
• [ ] AERROR - can't readfile CLTL2 because non-external LISP package FLOATING-POINT-UNDERFLOW.
• [ ] APRINT - similarly missing READTABLE-CASE (might interfere with multiple changes to APRINT)
• [ ] ATBL - CLTL2 is 1991; sources is 1993; \TYPEGLOBALVARIABLE 'READTABLEP
• [ ] ATERM - oldest sources is 1990, CLTL2 is 1992. diff comment
• [ ] BOOTSTRAP - oldest sources is 1992, CLTL2 is 1993 based on it. change package handling in \LOAD-STREAM to be more forgiving; add BOOTSTRAPNAMEFIELD
• [ ] BREAK-AND-TRACE ...

[masinter]

The methodology is emerging; the idea is to find a "merge base" between medley/sources and medley/CLTL2. Sometimes that's the oldest version of medley/sources in the repo (which was derived from Ron's dropbox). Sometimes the merge base is earlier. I haven't found too many explicit conflicts. I'm using a 3WAY utility that calls CSBROWSER(mergebase CLTL2) and CSBROWSER(mergebase sources).

If we don't have a merge base then it requires guessing which changes in CLTL2 vs early/original sources changes were for common lisp compatibility