Was there any rationale behind choosing C99 over C89? My university's microcontroller courses were all C89, which seems much more prevalent outside of GCC (in

Was there any rationale behind choosing C99 over C89? My university's microcontroller courses were all C89, which seems much more prevalent outside of GCC (in particular, Microsoft's C compiler). C89 might be seen as simpler and more bare-metal for an operating systems course owing to e.g. the inability to create runtime-sized arrays on the heap (despite the archaic refusal to accept variable declarations in for loops..).