their own licenses:
dlmalloc/ - CC0; see the notice in malloc.c for details
+emmalloc/ - MIT; see the notice in emmalloc.c for details
libc-bottom-half/cloudlibc/ - BSD-2-Clause; see the LICENSE file for details
-libc-bottom-half/libpreopen/ - BSD-2-Clause; see the notice in libpreopen.c for details
libc-top-half/musl/ - MIT; see the COPYRIGHT file for details
wasi-libc's changes to these files are multi-licensed under the