This is documented in TBR3 and is already declared in <misctool.h>, but did not previously have glue code. TBR3 says "Applications should never make this call," but it may be useful in system utilities.
Tabs have been expanded to spaces in several files that use mainly spaces for indentation.
The files ctype.asm, stdio.asm, and string.asm consistently use tabs for indentation. The tabs in these files have been left alone, except that a few tabs between sentences in comments were changed to spaces. One space-indented line in stdio.asm was changed to use a tab.