/usr/src/$pkgname-$pkgver doubts

[gapan]

Nothing needs to be compiled in /usr/src. But as others already pointed out its usual to do so in many systems. /usr/src is the place to put source files. And it's a far better choice that /usr/doc, which should be used, unsurprisingly, for documentation. Slackware packages don't include any build scripts in the package. The fact that Salix packages do, is a convenience, not a requirement. A convenience which introduces no incompatibility whatsoever.

[pwatk]

Okay, I think of compiling the kernel under /usr/src. This makes the most sense to me cause of the dependency (headers), but I can not imagine any other package which *needs* to be build unter /usr/src directly.

I agree.

I didn't say anything *needs* to be built under /usr/src directly

Nothing needs to be compiled in /usr/src. But as others already pointed out its usual to do so in many systems. /usr/src is the place to put source files. And it's a far better choice that /usr/doc, which should be used, unsurprisingly, for documentation. Slackware packages don't include any build scripts in the package. The fact that Salix packages do, is a convenience, not a requirement. A convenience which introduces no incompatibility whatsoever.

I agree.