Remove command line options -U and -i

[ChrisJefferson]

The two command line options -U (set compiler options) and -i (set GAP root file) have been broken since at least 4.7.2, so let's remove them.

The reason this came to light is the way in which -U is broken causes the code coverage to wobble. The option was ignored anyway. Any use of -i would just cause GAP to not start correctly with a weird error message.

[fingolfin]

For the record, these options were already broken in GAP 4.4.12, the breakage was introduced in a commit on 2002-10-23.

[fingolfin]

It is somewhat sad that compiler options are going, though. Perhaps we should retain -U instead and fix it (which doesn't look too hard), possibly under a different (long) name like --compiler-args.

Then again, nobody used them... And I am so sure how useful those compiler options ever were.

[ChrisJefferson]

Also, fixing --compiler-args is not just fixing the argument, even after fixing the parsing, we still ignore it anyway as we just hard-wire the options in InitKernel, and after a (very brief) investigation, if you turn all the options off the compiler produces code that doesn't even compile.

[fingolfin]

Another remark: -i and -U are mentioned in the manual, in doc/ref/run.xml -- so that file needs to be modified, too.

[ChrisJefferson]

Docs now fixed.

[codecov]

Codecov Report

Merging #1265 into master will increase coverage by <.01%.
The diff coverage is 71.42%.

@@            Coverage Diff             @@
##           master    #1265      +/-   ##
==========================================
+ Coverage   57.19%   57.19%   +<.01%     
==========================================
  Files         923      923              
  Lines      281761   281739      -22     
  Branches    15901    15863      -38     
==========================================
- Hits       161155   161145      -10     
+ Misses     117578   117571       -7     
+ Partials     3028     3023       -5

Impacted Files	Coverage Δ
src/compiler.c	61.18% <ø> (+0.12%)	⬆️
lib/system.g	66.97% <ø> (ø)	⬆️
src/gap.c	52.54% <100%> (ø)	⬆️
src/system.c	51.86% <100%> (-0.17%)	⬇️
hpcgap/src/gap.c	17.5% <33.33%> (+0.03%)	⬆️

[markuspf]

Needs rebase after recent merge.

I think if we ever do anything about the compiler we might feel the need for compiler options, but then the compiler should be a separate binary with its own command line options, anyway.

[fingolfin]

Still am happy with this. So far no complaints in reaction to @ChrisJefferson's mail on the removal. So I think @markuspf can merge this whenever he wants, if he agrees with the premise of the PR (which I assume he does).

[fingolfin]

Nitpick: this Pr call could now b fused with the following one.