Fix build issues in SimpleIDE

[martinmaly]

• Fix ctags build; ctags used __unused__ and __printf__ macros which
  conflict with GCC macro definitions in later versions of GCC.
  Fix (rename the macros) was brought over from future versions of ctags.
• Update plinrelease.sh:
  • qmake version detection made reliable using qmake -query instead of
    relying on the Qt installation path
  • Clone Simple-Libraries from the updated repository, clean up .git
    instead of .hg directory.
  • Fix sh incompatibilities (use of popd)
• Create a github action to build SimpleIDE on push and pull request.