Compilation warnings for MacOS

[rs028]

I noticed these warnings on the testsuite logs for macos only (both version 11 and 12). Likely not very serious, but to be checked.

Not sure if this can be a potential source of error:

call mech_converter.py
/Users/runner/work/AtChem2/AtChem2/./build/mech_converter.py:75: SyntaxWarning: invalid escape sequence '\-'
  symbol_regex = '[()\-+*@/, ]+'
/Users/runner/work/AtChem2/AtChem2/./build/mech_converter.py:76: SyntaxWarning: invalid escape sequence '\-'
  nonsymbol_regex = '[^()\-+*@/, ]+'
/Users/runner/work/AtChem2/AtChem2/./build/mech_converter.py:307: SyntaxWarning: invalid escape sequence '\('
  func_def_pat = "function +([a-zA-Z0-9_]*) *\("

This one can probably be ignored (?):

ld: warning: dylib (cvode/lib/libsundials_cvode.dylib) was built for newer macOS version (11.7) than being linked (11.0)
ld: warning: dylib (cvode/lib/libsundials_nvecserial.dylib) was built for newer macOS version (11.7) than being linked (11.0)
ld: warning: dylib (cvode/lib/libsundials_fnvecserial.dylib) was built for newer macOS version (11.7) than being linked (11.0)
ld: warning: object file (cvode/lib/libsundials_fcvode.a(fcvbp.c.o)) was built for newer macOS version (11.7) than being linked (11.0)
ld: warning: object file (cvode/lib/libsundials_fcvode.a(fcvode.c.o)) was built for newer macOS version (11.7) than being linked (11.0)