[issue46848] Use optimized string search function in mmap.find()
benrg added the comment: memmem isn't a standard C function, and some libraries don't have it, notably Microsoft's. newlib's memmem seems to be the same as glibc's, but is under a BSD 3-clause license instead of LGPL. An older version of newlib's memmem (prior to 2019-01-01) has the license
