Use the ccall macro in kb07, mc21 and mc77

[amontoison]

I also fixed an error in mc77, a is a Ptr{$elty} and not a Ptr{Cint}. I don't understand why It was working before...

[codecov[bot]]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (0b201ff) 75.05% compared to head (e2649ba) 75.05%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #172 +/- ## ======================================= Coverage 75.05% 75.05% ======================================= Files 7 7 Lines 449 449 ======================================= Hits 337 337 Misses 112 112 ``` | [Impacted Files](https://codecov.io/gh/JuliaSmoothOptimizers/HSL.jl/pull/172?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=JuliaSmoothOptimizers) | Coverage Δ | | |---|---|---| | [src/kb07.jl](https://codecov.io/gh/JuliaSmoothOptimizers/HSL.jl/pull/172?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=JuliaSmoothOptimizers#diff-c3JjL2tiMDcuamw=) | `100.00% <100.00%> (ø)` | | | [src/mc21.jl](https://codecov.io/gh/JuliaSmoothOptimizers/HSL.jl/pull/172?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=JuliaSmoothOptimizers#diff-c3JjL21jMjEuamw=) | `93.75% <100.00%> (ø)` | | | [src/mc77.jl](https://codecov.io/gh/JuliaSmoothOptimizers/HSL.jl/pull/172?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=JuliaSmoothOptimizers#diff-c3JjL21jNzcuamw=) | `92.20% <100.00%> (ø)` | | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=JuliaSmoothOptimizers). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=JuliaSmoothOptimizers)

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[JSOBot]

Testing HSL tests passed: https://gist.github.com/aced71c08bba8f03b508222314df1525

[JSOBot]

Testing HSL tests passed: https://gist.github.com/JSOBot/75c172211646f034d41f658373e1367c

[JSOBot]

Testing HSL tests passed: https://gist.github.com/JSOBot/be725adadaa43f8813bc08cfc165d75f