These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.04 s (backtrack: 0/20).

[ebuild  N     ] media-libs/glm-1.0.3::gentoo  USE="-test" CPU_FLAGS_X86="avx avx2 sse2 sse3 sse4_1 sse4_2 ssse3" 4490 KiB
[ebuild  N     ] media-libs/libprojectm-3.1.12-r4:0/2::gentoo  USE="-gles2 -sdl" 51594 KiB

Total: 2 packages (2 new), Size of downloads: 56084 KiB