Incorporate Gentoo patches

Gentoo builds have a few minor patches which we would like to see incorporated. These target 10.0.15. We do have patches for 5.5 series as well

The purpose of each patch:
01050_all_mariadb_mysql_config_cleanup-5.5.41.patch - fix Gentoo bug #156301 mysql_config wrongly retains too much info from CFLAGS (we've been using this for many years)

20004_all_mariadb-filter-tokudb-flags-10.0.7.patch - Filter out -flto -fuse-linker-plugin -g and -Werror for tokudb – Werror is banned in builds for us, -g is not always wanted, and the others are a bit aggressive.

20006_all_cmake_elib-mariadb-10.0.15.patch - Add ELIBPATH to split client and embedded libs; Also make static libs selectively installed by ENABLE_STATIC_LIBS (mimics autotools option which no longer exists)

20009_all_mariadb_myodbc_symbol_fix-5.5.38.patch - Export missing symbols at runtime for myodbc