Seems that GL/glext.h now exports functions for GL_ARB_shader_objects extension, so they define GL_ARB_shader_objects, which results in relevant section being skipped in /usr/include/GLee.h.
By default GL/glext.h skips defining prototypes for functions, but it can be enabled - I used -DGL_GLEXT_PROTOTYPES option to gcc, and compilation finished without errors.
Apparently you can not compare wxstrings implicitly anymore. So convert the wxstrings to wstrings explicitly.
See also: https://bugs.gentoo.org/887055 https://github.com/prusa3d/PrusaSlicer/issues/9294
The other commit:
See also: https://github.com/stefantalpalaru/gentoo-overlay/issues/26