Trying to solve GAUSSFIT issue

[alaingdl]

This patch should solve #1662. It is working now on Linux and OSX. some code will be discarded ASAP. Few others details solved. I am very sorry but no test_gaussfit up to now :disappointed: , but I have a draft :smiley_cat:

When we will have more time, it would be good to fix some of the warnings triggered by the use of the -Wall flag, especially in the core code ... (see my small change in dimension.hpp :

54c54
<     for(SizeT i=0; i<rank; ++i)
---
>     for(char i=0; i<rank; ++i)

)

[codecov[bot]]

Codecov Report

Attention: 26 lines in your changes are missing coverage. Please review.

Comparison is base (f29c1fa) 41.17% compared to head (4052329) 41.07%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1663 +/- ## ========================================== - Coverage 41.17% 41.07% -0.11% ========================================== Files 356 356 Lines 95066 95061 -5 Branches 19537 19539 +2 ========================================== - Hits 39146 39045 -101 - Misses 55920 56016 +96 ``` | [Files](https://app.codecov.io/gh/gnudatalanguage/gdl/pull/1663?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=gnudatalanguage) | Coverage Δ | | |---|---|---| | [src/dimension.hpp](https://app.codecov.io/gh/gnudatalanguage/gdl/pull/1663?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=gnudatalanguage#diff-c3JjL2RpbWVuc2lvbi5ocHA=) | `90.41% <100.00%> (ø)` | | | [src/math\_fun\_ac.cpp](https://app.codecov.io/gh/gnudatalanguage/gdl/pull/1663?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=gnudatalanguage#diff-c3JjL21hdGhfZnVuX2FjLmNwcA==) | `35.31% <ø> (ø)` | | | [src/gsl\_fun.cpp](https://app.codecov.io/gh/gnudatalanguage/gdl/pull/1663?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=gnudatalanguage#diff-c3JjL2dzbF9mdW4uY3Bw) | `40.06% <27.77%> (-0.37%)` | :arrow_down: | ... and [13 files with indirect coverage changes](https://app.codecov.io/gh/gnudatalanguage/gdl/pull/1663/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=gnudatalanguage)

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[alaingdl]

problem only with the TIC/TOC reported in #1661

[GillesDuvert]

the changes in dimension.hpp should be explained (even if apparently inocuous) (this is legacy touchy code). the calls ofSizeT nParam = e->NParam(xxx); in la_trired_proand other functions of gsl_fun is important, even if 'nParam' is reported unused. by the compiler. In that case, replace, e.g., nParam = e->NParam(3); by e->NParam(3); avoiding creating a variable.