* include/libmes.h (abtod): Declare.
* lib/mes/abtod.c: New file.
* build-aux/configure-lib.sh (libmes_SOURCES, libc_tcc_SOURCES): Add
it.
* lib/mes/abtol.c: Update.
* lib/stdlib/strtod.c: Use it to implement; move from stub/strtod.
* lib/tests/mes/90-abtod.c: Test it.
* lib/tests/mes/90-abtod.stdout: Baseline.
* build-aux/check-mescc.sh (tests): Run it.
