Hello!
This is my first time posting, so do feel free to correct me and
this post.
I started writing in D around Q2 2017 and recently been
re-writing some of my projects as betterC (entirely!).
I noticed something weird. It started with DMD 2.074.0 and it's
still an issue for me in DMD 2.079.1 (and any other compiler
really).
Consider this piece:
```
import core.stdc.stdio;
extern(C) void main() {
printf("a");
}
```
It compiles and runs absolutely wonderful (OMF, MSCOFF, ELF,
etc.). No issues.
Now consider this piece:
```
import core.stdc.stdio;
extern(C) void main() {
putchar('a');
}
```
Oops, `Error 42: Symbol Undefined
__D4core4stdc5stdio7putcharFNbNiNeiZi`! To my surprise, `putchar`
is extern'd as D in druntime/src/core/stdc/stdio.d, and I find
that _really silly_.
Which means `putchar`, during linking, is affected for linking
every single C runtime out there, and the only reason I can think
of is to easily integrate it with D in general, which in my
opinion, is not necessarily needed since the D people (not meant
as an insult) promotes betterC as a stand-alone option.
On Windows, stdin, stdout, and stderr are affected when using
-m32mscoff and -m64 (and obviously, LDC) because under
CRuntime_Microsoft, std* are defined as `shared`.
I'm aware that an easy solution would be defining a version
(D_betterC) section.
Will I do a Pull Request? Unfortunately no, I fear I'll abandon
mid-way through. It's easier to advise the forums and let an
actual professional integrate the fix.
If you have other suggestions, I'm all ears.
