Attempt to fix MacOS PGO build

[Cryoris]

Summary

Link Python library manually in the PGO build, which works out locally. This is done inside build_pgo.sh instead of the wheels-build.yml to ensure the correct Python library is found. This is more of a backup solution, it would be nicer if PyO3/Rust would be able to link the required libraries automatically (maybe we're missing some flag).

Details and comments

Possibly this needs an additional DYLD_LIBRARY_PATH export, but let's see what the wheels say...

[qiskit-bot]

One or more of the following people are relevant to this code:

• @Qiskit/terra-core

[ElePT]

May the wheels be with you

[coveralls]

Pull Request Test Coverage Report for Build 13793277941

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 10 unchanged lines in 3 files lost coverage.
• Overall coverage increased (+0.009%) to 88.139%

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Files with Coverage Reduction	New Missed Lines	%
crates/accelerate/src/unitary_synthesis.rs	1	94.69%
crates/qasm2/src/lex.rs	3	92.48%
crates/qasm2/src/parse.rs	6	97.61%

Totals
Change from base Build 13792557824:	0.009%
Covered Lines:	72643
Relevant Lines:	82419

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💛 - Coveralls

[Cryoris]

They were not (quite)... the build_pgo.sh script now runs successfully but it's still not finding the libraries in the final build of the optimized binary.

[Cryoris]

As side note: changing the libtype of qiskit-cext from cdylib to staticlib works without requiring any library setting.