Build hangs when using single thread on Windows and Linux

[akarpovskii]

Zig Version

0.14.0-dev.1576+5d7fa5513

Steps to Reproduce and Observed Behavior

It was working fine on 0.13.0.
On master, zig build -j1 hangs at Code Generation on Windows and Linux, works well on macOS.

Repro:

• zig init an empty project.

• zig build -j1 --global-cache-dir "./.zig-global" hangs
  You may need to clear caches to reproduce the issue.

[2] Compile Build Script
├─ Semantic Analysis
├─ compiler_rt
│  └─ AST Lowering
├─ zig_libc
│  └─ AST Lowering
└─ Code Generation

Expected Behavior

zig build -j1 finishes successfully.

[chrboesch]

Can confirm this error on Linux even if you pass an absolute path.