fprintf(stderr, …) doesn't work in C wasm kernel

[anutosh491]

Clang-repl in C mode

anutosh491@vv-nuc:/build/anutosh491/llvm-project/build2/bin$ ./clang-repl --Xcc=-x --Xcc=c --Xcc=-std=c23
clang-repl> #include <stdio.h>
clang-repl> printf("some output\n");
some output
clang-repl> fprintf(stderr, "some error\n");
some error

But using the C wasm kernel

[anutosh491]

cc @davy39 would you like trying a fix ?

[davy39]

I can't get to it now, but I'll definitely take a look later if no one else has.