Add fixes for building on macOS

[shkodm]

• -E in sed to be POSIX compliant
• Remove regex in find to make it more tolerable and portable
• find models/ produces extra slashes in results on macos ( i.e. models//multiphase/) but not on Linux. find models does not give extra slashes and behaves the same as find models/ on models

Tested on my M2 Macbook Air, all the clusters where I use TCLB, and my workstation.

@TravisMitchell FYI

I will also CI at some point, but not in this PR.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (2081562) 38.15% compared to head (70075e6) 39.63%.

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #493 +/- ## =========================================== + Coverage 38.15% 39.63% +1.47% =========================================== Files 181 184 +3 Lines 8234 8477 +243 =========================================== + Hits 3142 3360 +218 - Misses 5092 5117 +25 ``` | [Flag](https://app.codecov.io/gh/CFD-GO/TCLB/pull/493/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=CFD-GO) | Coverage Δ | | |---|---|---| | [d2q9](https://app.codecov.io/gh/CFD-GO/TCLB/pull/493/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=CFD-GO) | `28.00% <ø> (ø)` | | | [d3q27_PSM_NEBB](https://app.codecov.io/gh/CFD-GO/TCLB/pull/493/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=CFD-GO) | `32.15% <ø> (ø)` | | | [d3q27_pf_velocity](https://app.codecov.io/gh/CFD-GO/TCLB/pull/493/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=CFD-GO) | `27.33% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=CFD-GO#carryforward-flags-in-the-pull-request-comment) to find out more.

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[shkodm]

Superseded by https://github.com/CFD-GO/TCLB/pull/495