Fix Windows signature compatibility in entity_id functions

[bwoebi]

Should fix PHP build for windows.

@VianneyRuhlmann Please check

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 69.24%. Comparing base (436c751) to head (1ea1e8e).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #474   +/-   ##
=======================================
  Coverage   69.24%   69.24%           
=======================================
  Files         195      195           
  Lines       26051    26051           
=======================================
  Hits        18039    18039           
  Misses       8012     8012           

Components	Coverage Δ
crashtracker	17.62% <ø> (ø)
datadog-alloc	98.76% <ø> (ø)
data-pipeline	51.45% <ø> (ø)
data-pipeline-ffi	0.00% <ø> (ø)
ddcommon	86.43% <ø> (ø)
ddcommon-ffi	74.15% <ø> (ø)
ddtelemetry	56.11% <ø> (ø)
ipc	84.53% <ø> (ø)
profiling	77.83% <ø> (ø)
profiling-ffi	59.61% <ø> (ø)
serverless	0.00% <ø> (ø)
sidecar	36.29% <ø> (ø)
sidecar-ffi	0.00% <ø> (ø)
spawn-worker	54.98% <ø> (ø)
trace-mini-agent	69.33% <ø> (ø)
trace-normalization	97.79% <ø> (ø)
trace-obfuscation	95.74% <ø> (ø)
trace-protobuf	33.33% <ø> (ø)
trace-utils	90.94% <ø> (ø)