The original version of GLEW contains files under 4 licenses:
BSD
GPLv2+
SGI Free Software License B
GLX Public License

The last 2 licenses are not Free software licenses and thus not acceptable for
Fedora. The version shipped by Fedora has the encumbered files removed and
replaced by files from Mesa. These replacement files are licensed under the
MIT license, which is BSD and GPL compatible.

Also note that the GPL licensed files are scripts which generate parts of the
C-code in GLEW, these scripts itself are only part of the GLEW sources shipped
by Fedora, not of the binary rpm. Thus the binary package is licensed under the
BSD license, and only under the BSD license. This is important for other
packages which use the GLEW library.