Remove unused #define PERCENT_OF_SCREEN in MyWindow.h
Move structures for dir.c to dirdefs.h where they are used
Resolve S_CHAR vs S_CHARACTER in favor of S_CHARACTER and cleanup #defines
Fix = vs == bug in FSDEBUG code in dir.c
Eliminate duplicate/unused constant definitions in gcr.c
Declare static internal function bytecmp in mkatom.c
Update many source and include files to include headers for what they use
Except where the expansion would be syntactically invalid,
for example "goto macroarg;" detection of which is a bug in clang-tidy,
so warn it off with a NOLINT...(bugprone-macro-parentheses)
As a prerequisite for cleaning up some other include issues, all the
include files in inc/ should have an include guard. All the xxxdefs.h
were created with them, but most older files were not.
