Avoid patching symbols in the extension module

[pablogsal]

The fact that patching ourselves had not raised problems so far its
really an outstanding fact in this universe. Unfortunately seems that
with the latest toolchain + GCC there is something that causes memray to
point the d_original entry of the hooks pointing to itself, which should
never happen.

To fix this resiliently, avoid patching ourselves by getting our own
name in the extension module and then avoiding that shared object.

Closes: #662

[godlygeek]

LGTM

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 87.50000% with 1 line in your changes missing coverage. Please review.

Project coverage is 92.79%. Comparing base (8635569) to head (ab83fcb).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/memray/_memray/linker_shenanigans.h	75.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #685      +/-   ##
==========================================
+ Coverage   92.75%   92.79%   +0.03%     
==========================================
  Files          94       95       +1     
  Lines       11470    11475       +5     
  Branches     2114     2114              
==========================================
+ Hits        10639    10648       +9     
+ Misses        831      827       -4     

Flag	Coverage Δ
cpp	92.79% <87.50%> (+0.03%)	⬆️
python_and_cython	92.79% <87.50%> (+0.03%)	⬆️

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[sethtroisi]

Thanks!

Out of curiosity did you also encounter this issue? if so do you have a guess which gcc versioned caused it?

[pablogsal]

Thanks!

Out of curiosity did you also encounter this issue? if so do you have a guess which gcc versioned caused it?

I encountered this only when compiling memray with gcc 14 and python compiled with -no-pie. It may be a linker bug because that fields should never end in the PLT with a relocation.