Its sources reached the standard library through the project headers they
included; those are imports now. 178 headers across 56 files, plus 18 C
library headers elsewhere for memcpy/printf and friends. MSVC's STL does
not supply these transitively the way libstdc++ does.
Unqualified uint8_t/size_t and friends were reaching 24 units through
some other header on libstdc++; MSVC's STL does not do that, which broke
gl/ubo.cppm (and made its UBS_PAD macro look like garbage). Also
silences C5244, MSVC's counterpart to the clang warning about glm being
included in the module purview, which is deliberate here.
