Remove IPO for nanobind target

[pramodk]

• When nanobind is compiled with IPO, the build with compilers like IntelOneAPI and binutils ld v2.41 can fail

icpx -fPIC  -fopenmp-simd -g  -O2   …. ../../lib/libnanobind.a -pthread
/gpfs/bbp.cscs.ch/ssd/apps/bsd/2024-02-01/stage_compilers/install_gcc-4.8.5-haswell/binutils-2.41-o6yabj/bin/ld: ../../lib/libnanobind.a: error adding symbols: file format not recognized
icpx: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [lib/libnrniv.so] Error 1

• This is because, with the -ipo flag, the generated object file is LLVM bitcode

$ file CMakeFiles/nanobind.dir/__/__/external/nanobind/src/nb_combined.cpp.o
CMakeFiles/nanobind.dir/__/__/external/nanobind/src/nb_combined.cpp.o: LLVM bitcode

• By reading some issues/posts, this is supposed to work transparently via linker but example like BB5 CI failures indicate this is still fragile.

@alkino: If the IPO is not really necessary for this nanobind target then I suggest a simple option is to remove IPO. Note that you added IPO for only RELEASE build and hence this didn't fail in our CI earlier.

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[azure-pipelines[bot]]

✔️ 4660765156d4bff3e5a195781188184a0ca83113 -> Azure artifacts URL

[codecov[bot]]

Codecov Report

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

Project coverage is 67.26%. Comparing base (79ad349) to head (4660765). Report is 1 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #2961 +/- ## ========================================== - Coverage 67.27% 67.26% -0.01% ========================================== Files 571 571 Lines 104868 104879 +11 ========================================== + Hits 70547 70549 +2 - Misses 34321 34330 +9 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[bbpbuildbot]

Logfiles from GitLab pipeline #220538 (:white_check_mark:) have been uploaded here!

Status and direct links:

• :white_check_mark: mac_m1_cmake_build: [cmake, ON, OFF, OFF, address]
• :white_check_mark: spack_setup
• :white_check_mark: build:nmodl
• :white_check_mark: build:neuron:nmodl:intel:legacy
• :white_check_mark: build:neuron:nmodl:intel:shared
• :white_check_mark: build:neuron:nmodl:nvhpc:acc:legacy
• :white_check_mark: build:neuron:nmodl:nvhpc:acc:shared
• :white_check_mark: build:neuron:nmodl:nvhpc:omp:legacy
• :white_check_mark: build:neuron:nmodl:nvhpc:omp
• :white_check_mark: test:neuron:nmodl:intel:legacy
• :white_check_mark: test:neuron:nmodl:intel:shared
• :white_check_mark: test:neuron:nmodl:nvhpc:acc:legacy
• :white_check_mark: test:neuron:nmodl:nvhpc:acc:shared
• :white_check_mark: test:neuron:nmodl:nvhpc:omp:legacy
• :white_check_mark: test:neuron:nmodl:nvhpc:omp