Notice in the make.log it says:
3 warnings generated when compiling for gfx803.
When you actually wanted 90a. You can try compiling with VERBOSE=1 to see the exact compiler flags. (I'm annoyed that CMake hides all of this — it makes debugging so much harder. But then with verbose, it is too verbose.)
make VERBOSE=1
In CMakeLists.txt, try adding 90a to this list:
set(VALID_GFXS "700;701;702;703;704;705;801;802;803;805;810;900;902;904;906;908;909;90c;1010;1011;1012;1030;1031;1032;1033")
and recompile everything.
Mark