make induced changes

Calling make results in file changes that results in a full re-compilation.

This means if you follow the standard safe procedure of:
```
make
make install
```

nginx gets largely re-compiled for make install.

Start by running the reported sequence, `make` followed by `make install`, and inspect which files change between the two commands. Trace the build inputs that cause nginx to be largely recompiled; done means the standard sequence no longer induces unnecessary file changes or a full rebuild.

Written by the indexing model from the issue text.