[build2] How to detect and configure #define macros?

[Boris Kolpackov]

Joshua Olson <0joshua.olson1 at gmail.com> writes:

> I'm gonna see if I can make a JUCE package...

Sounds good. If you would like, I can publish it on cppget.org (in the
future there will be an automated way to do it but for now I can do it
manually if you give me a git repo).


> Comment: the src-url of https://cppget.org/libodb is broken (
> https://git.codesynthesis.com/cgit/?p=odb/libodb.git;a=tree says 'invalid
> request')

Fixed, thanks!


> Question: if package A depends on a semi-popular package B being installed
> (e.g. libcurl, webkit, gtk headers on Linux), is it ever preferable for
> package B to be a bpkg too?

Good question. In bpkg we have a notion of stub packages. Quoting from
the bpkg manual[1]:

"Version 0 (with a potential revision, for example, 0+1, 0+2) is used
to signify a stub package. A stub is a package that does not contain
source code and can only be "obtained" from other sources, for example,
a system package manager. Note that at some point a stub may be converted
into a full-fledged package at which point it will be assigned a "real"
version."

You can see an example of a stub here:

https://git.build2.org/cgit/packaging/apr/libapr1/

Currently, the only way to install a package via a stub is to tell bpkg
that it is already system-installed, for example:

$ bpkg build sys:libcurl libjuce

In the future, however, we are thinking of having bpkg query the system
package manager (e.g., apt, dnf, pkg, etc) and if the package is not
installed, offering to install it.

So, to put this all together, currently, if you do not want (yet) to
package some dependencies but would like to list them as dependencies
in the manifest, then the way to go is to create a stub.

The reason you may at some point want to convert a stub to a full
package is Windows: it doesn't have a system package manager (though
I hear vcpkg may be becoming something like that) which makes
installing dependencies painful. For example, we have started with
libpq (PostgreSQL client library) as a stub but have now made it a
real package which made life on Windows so much easier.

[1] https://build2.org/bpkg/doc/build2-package-manager-manual.xhtml

Boris