SYSROOT vs --with-xxx-prefix

[Alon Bar-Lev]

Hi,

gnupg packages require xxx-config scripts instead of using pkg-config
for gnupg project in-house dependencies, I am unsure what the reason
is, but it makes integration with gnupg a bit harder for downstream.
In recent years gnupg projects already use pkg-config for 3rd party
dependencies so I guess it is not taboo these days.

In any case, in order to configure the in-house dependencies there are
three options:
1. Specify XXX_CONFIG with location of each individual config script.
2. Specify --with-xxx-prefix with prefix of bin/xxx-config script per
each dependency.
3. Specify SYSROOT as global --with-xxx-prefix.

When performing cross-compile all the dependencies should be
re-configured, these that use pkg-config are simple, using SYSROOT for
the in-house dependencies would have been nice.

However, SYSROOT is not supported by all m4 macros of in-house dependencies.

In addition, the SYSROOT searches config only at SYSROOT/bin and not
SYSROOT/usr/bin making it harder to integrate with the sysroot concept
of the cross compiler.

Summary
1. Farfetched... can we support pkg-config? I can help to support this
in parallel to the existing mechanism.
2. Can you please add SYSROOT support for all dependencies? (npth, ksba, assuan)
3. Can you please search in both SYSROOT/bin and SYSROOT/usr/bin for
config script?

Thanks,
Alon