man(1): avoid endless loop in .so includes

[wosch]

Summary

I think the solution is to limit the number of includes to a value of 10 instead infinity.

See https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=287037

[wosch]

Simplify while loop & fix an indent issue.

[imp]

10 might be too small. But if so, it's easy to bump to 20

[emaste]

Is it worth emitting a warning on stderr if we exit the loop due to the limit?

[wosch]

In D51412#1173928, @imp wrote:

10 might be too small. But if so, it's easy to bump to 20

I checked the ports manual pages. The highest number of includes is 8. On Linux the zshall.1 has 15 includes. I will increase the limit to 32.

[wosch]

Increase .so include limit to 32, and display a warning if we reach the limit in debug mode.