How to apply glibc patches

The GNU libc patches replace the current GNU libc implementation (which is usually not correctly-rounded) by a correctly-rounded one. To use the GNU libc patches, for example, once you have downloaded the cbrt-binary32 patch (named cbrtf-as.patch):
$ git clone https://sourceware.org/git/glibc.git
$ cd glibc
$ patch -p1 -i cbrtf-as.patch
$ mkdir build
$ cd build
$ ../configure --prefix=/usr CC="gcc -march=native"
$ make -j4
$ make bench
then you can look in the file benchtests/bench.out the entry "cbrtf". Alternatively once you have done make bench you can do ./testrun.sh benchtests/bench-cbrtf.

The license of the files modified by the patch is the common denominator of the license of the CORE-MATH file and the license of the corresponding GNU libc file.