Log Message:
libepoxy: update to 1.5.9.

Changes since 1.5.8

    Allow libopengl.so to be used when GLX_LIB is missing [#257, John Bates]

Changes since 1.5.7

    Revert changes from PR #238 / #229
    Fixes regressions: #240, #252, #253

Changes since Epoxy 1.5.6

    Remove type redefinition [#249]

Changes since 1.5.5

    Fix issue with loading OpenGL/GLX/EGL libraries [#238, Yaroslav Isakov]
    Expose dependency variables in pkg-config file [#231, Xavier Claessens]
    Support Win64 pointer-sized types [#246]
    Close output objects when generating files [#242, Aleksandr]

Changes since 1.5.4

    Remove Python 2 support [#213]
    Remove Autotools support [#212]
    Use EGL_NO_X11 to disable X11 headers [#216]
    Use call convention for mock function [crziter, #220]
    Return correct version of GLSL on GLES2 [Eric Anholt, #223]
    Rely on Meson's darwin_versions option [#225]