Mea upstream after 49e2275d0d67696662b4e0008a72b9004826feed requires >=x11-libs/libdrm-2.4.56. Unfortunately no such ebuild exists yet. checking for RADEON... no checking for RADEON... configure: error: Package requirements (libdrm_radeon >= 2.4.56) were not met: Requested 'libdrm_radeon >= 2.4.56' but version of libdrm_radeon is 2.4.54 Consider adjusting the PKG_CONFIG_PATH environment variable if you installed software in a non-standard prefix. http://cgit.freedesktop.org/mesa/mesa/commit/configure.ac?id=49e2275d0d67696662b4e0008a72b9004826feed
I pushed an update to mesa-9999, but I'm having trouble updating the solaris patch against libdrm, so I haven't pushed a .56 bump.