src,lib: expose memory file mapping flag
Support for UV_FS_O_FILEMAP
was added in libuv in version 1.31.0. This exposes the flag in fs.constants and adds the prefix 'm'
for text flags.
New functionality is added, so this is semver minor.
cc @nodejs/platform-windows
Checklist
-
make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
tests and/or benchmarks are included -
documentation is changed or added -
commit message follows commit guidelines