Add LLVM_SYS_170_PREFIX export to env-macos.sh

[fmoletta]

Following the MacOs setup in the Getting Started section of the README leads to an error when running make test as the env var LLVM_SYS_170_PREFIX is not set. This PR adds this export to the env-macos.sh script.

[github-actions]

Benchmarking results

Benchmark for program factorial_2M

Open benchmarks

Command	Mean [s]	Min [s]	Max [s]	Relative
Cairo-vm (Rust, Cairo 1)	20.839 ± 0.158	20.694	21.220	43.58 ± 0.38
cairo-native (JIT MLIR ORC Engine)	1.571 ± 0.015	1.545	1.591	3.28 ± 0.04
cairo-native (AOT Native binary)	0.661 ± 0.001	0.659	0.663	1.38 ± 0.01
cairo-native (AOT Native binary with host CPU features, march=native)	0.478 ± 0.002	0.477	0.484	1.00

Benchmark for program fib_2M

Open benchmarks

Command	Mean [s]	Min [s]	Max [s]	Relative
Cairo-vm (Rust, Cairo 1)	20.286 ± 0.048	20.203	20.341	648.03 ± 3.82
cairo-native (JIT MLIR ORC Engine)	1.113 ± 0.012	1.097	1.130	35.57 ± 0.44
cairo-native (AOT Native binary)	0.031 ± 0.000	0.031	0.032	1.00 ± 0.01
cairo-native (AOT Native binary with host CPU features, march=native)	0.031 ± 0.000	0.031	0.032	1.00

Benchmark for program logistic_map

Open benchmarks

Command	Mean [s]	Min [s]	Max [s]	Relative
Cairo-vm (Rust, Cairo 1)	1.903 ± 0.012	1.881	1.924	27.17 ± 0.19
cairo-native (JIT MLIR ORC Engine)	1.423 ± 0.021	1.394	1.459	20.31 ± 0.30
cairo-native (AOT Native binary)	0.110 ± 0.004	0.109	0.132	1.57 ± 0.06
cairo-native (AOT Native binary with host CPU features, march=native)	0.070 ± 0.000	0.070	0.071	1.00

[codecov-commenter]

Codecov Report

Attention: 149 lines in your changes are missing coverage. Please review.

Comparison is base (87d0c98) 74.27% compared to head (efaf1d6) 73.90%.
Report is 1 commits behind head on main.

Files	Patch %	Lines
src/bin/cairo-native-compile.rs	0.00%	134 Missing ⚠️
src/ffi.rs	88.46%	15 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #359      +/-   ##
==========================================
- Coverage   74.27%   73.90%   -0.37%     
==========================================
  Files          96       97       +1     
  Lines       21889    22153     +264     
==========================================
+ Hits        16257    16372     +115     
- Misses       5632     5781     +149     

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