* lib/libc+tcc-gcc.c: New file: Libc bits for GCC from libc-mes+tcc.c.
* lib/libc+tcc-mes.c: New file: Libc bits for MesCC from libc-mes+tcc.c.
* lib/libc+tcc.c: New file: Libc bits from libc-mes+tcc.c.
* lib/libc.c: New file: Merged from libc-mes.c, libc-gcc.c.
(abtoi): New function: Rename from _atoi.
* lib/linux+tcc-gcc.c: New file: Linux bits from libc-gcc+tcc.c.
* lib/linux+tcc-mes.c: New file: Linux bits from libc-mes+tcc.c.
* lib/linux-gcc.c: New file: Linux bits from libc-gcc.c.
* lib/linux-mes.c: New file: Linux bits from libc-mes.c.
* lib/mini-libc-gcc.c: New file.
* lib/mini-libc.c: New file: Libc bits from mini-libc-mes.c.
* lib/mini-linux-gcc.c: New file.
* lib/mini-linux-mes.c: New file: Linux bits from mini-libc-mes.c.
* lib/libc-gcc.c: Remove duplication using include now.
* lib/libc-mes.c: Likewise.
* lib/mini-libc-mes.c: Likewise.
* include/stdio.h (puts)[POSIX]: Remomve macro.
(fputc, fputs)[!POSIX]: New macro.
(fputc, fputs): Remove declaration.
* scaffold/tests/7j-strtoull.c (strtoull, test): Use abtoi.
* src/lib.c (fputs)[__MESC__]: Remove define.
* guile/guix/make.scm: Update for new library layout.
* make.scm: Likewise.
* build.sh: Likewise.
* install.sh: Likewise.