The header-only static-inline error()/error_at_line() collided with gnulib's own
lib/error.c ('redefinition of error', building m4): autotools link-detects a
system error(), skips its replacement, then the inline in <error.h> clashes with
gnulib's definition. Implement them properly in relibc (src/header/error) with
the glibc globals (error_message_count, error_one_per_line, error_print_progname)
and make <error.h> a pure extern declaration. Fixes m4/gnulib and keeps
mesa/libelf (the original <error.h> consumers) working via the real symbol.
vasilito
1a6d3221b2