graphic: 0.981
debug: 0.961
boot: 0.961
user-level: 0.862
kernel: 0.838
device: 0.781
performance: 0.732
architecture: 0.726
register: 0.621
x86: 0.619
semantic: 0.587
i386: 0.558
ppc: 0.533
risc-v: 0.531
socket: 0.525
vnc: 0.519
peripherals: 0.513
KVM: 0.468
arm: 0.465
permissions: 0.464
network: 0.455
PID: 0.449
files: 0.447
VMM: 0.431
hypervisor: 0.413
TCG: 0.381
virtual: 0.242
mistranslation: 0.198
assembly: 0.191

Serial output mangled in terminal
Description of problem:
My hobby OS uses the serial port at `0x3f8` to log messages to QEMU's stdout. This used to work fine, I can even emit ANSI escape codes to get color output and it renders in my terminal as expected. I left this project for about a year and just returned to it with the latest version of QEMU. Now, all of the QEMU serial output from my OS in the terminal seems to be missing carriage returns and buffering strangely. It's as if every log line ends up on the same line in the stdout buffer, but with newlines (without returning to the start of the line) between them. For example (these aren't my real logs but demonstrate the issue):
```
[KERNEL] startup
                [KERNEL] initializing heap
                                          [KERNEL] initializing drivers
                                                                       [KERNEL] ready!
```
Also, when QEMU exits, I notice that my shell indicates that the last command's output didn't end in a newline which is strange.

I tried debugging this myself by piping the output to a file and inspecting it in a hex editor, but it looks like just normal newlines in the output. I tried piping the output to `tr '\n' '\r\n'` to add carriage returns, but that ends up rendering all the output on a single line which resets to the first column every line. I tried sending the output to a file and watching the file, but it seems to get buffered and the data only shows up once QEMU exits. My best guess is that the output hasn't changed, but this new version of QEMU is changing some kind of buffering setting on its output which is causing this, but I'm really not sure what's going on.
Steps to reproduce:
I can provide the boot image if that would be helpful to reproduce.
Additional information: