FABIC: musl : ctype.h : fixed missing enum { _ISupper, _ISlower, ..., _ISalnum }

"Blindly" imported from glibc (source) ctype/ctype.h
FABIC: musl : features.h : fixed missing #define __GLIBC_PREREQ(maj, min).

Found in /usr/include/features.h
FABIC: musl : stdio.h : fixed (removed) const-ness of stdin, stdout & stderr

As per Glibc's decl.
FABIC: musl : stdlib.h : fixed missing strtoll_l() & strtoull_l() by means of 2 macros for these o_O
FABIC: functions.sh : New checkenv().