ydb/contrib/libs/libc_compat

This library implements a compatibility layer between various libc implementations.

The rationale for the library implementation is described in https://st.yandex-team.ru/IGNIETFERRO-1439.

The code is taken from multiple sources, thus both LICENSE() and VERSION() tags are not very representative.

During development one can make use of the following mapping of OS_SDK into glibc version.

Ubuntu	glibc
20.04	2.30
18.04	2.27
16.04	2.23
14.04	2.18
12.04	2.15
10.04	2.11

Use the following commands to update the table above:

1. ya make util -DOS_SDK=ubuntu-xx -G | grep OS_SDK_ROOT | head -n 1
2. cd ~/.ya/tools/v4/$RESOURCE_ID
3. readelf -V $(find . -name 'libc.so.6')
4. Take the latest version from .gnu.version_d section prior to GLIBC_PRIVATE