[3.7] bpo-35550: Fix incorrect Solaris define guards (GH-11275) by miss-islington · Pull Request #11383 · python/cpython
Python source code uses on several places ifdef sun or defined(sun) without the underscores, which is not standard compliant and shouldn't be used.
Defines should check for __sun instead. Reference: http://nadeausoftware.com/articles/2012/01/c_c_tip_how_use_compiler_predefined_macros_detect_operating_systemGH-Solaris
https://bugs.python.org/issue35550
(cherry picked from commit 6f9bc72)
Co-authored-by: Jakub Kulík Kulikjak@gmail.com