[Git] Also ignore build dir if it's a symlink

[SFrijters]

Description

Build dir is commonly a symlink to a scratch space in my setup, it would be nice to ignore that case as well.

[codecov]

Codecov Report

Merging #536 (a95c3fa) into main (9a18e7c) will increase coverage by 0.00%.
The diff coverage is n/a.

❗ Current head a95c3fa differs from pull request most recent head 83859ce. Consider uploading reports for the commit 83859ce to get more accurate results

@@           Coverage Diff           @@
##             main     #536   +/-   ##
=======================================
  Coverage   76.59%   76.60%           
=======================================
  Files         263      263           
  Lines       19472    19474    +2     
=======================================
+ Hits        14915    14918    +3     
+ Misses       4557     4556    -1     

Impacted Files	Coverage Δ
src/occa/internal/utils/sys.cpp	76.56% <0.00%> (+0.10%)	⬆️
src/occa/internal/lang/specialMacros.cpp	60.26% <0.00%> (+0.66%)	⬆️