build: support out-of-tree compilation for id3 plugin

[Tarnyko]

Some build systems, such as Yocto, use a separate directory to output compilation results.

Creating an id3 source file with gawk using given syntax will then fail, because the output directory is invalid. Even if it was, there is a risk for the rest of the process to fail if it looks for the generated file inside the source tree instead of the build tree.

Thus, fix this by forcing creation inside the source tree.

Signed-off-by: Manuel Bachmann [email protected]

[Tarnyko]

Hi folks,

Please consider this commit, which allows building latest version under Yocto/OpenEmbedded.

[barbieri]

Are you sure this is the best approach for out-of-tree builds? What if we generate it in builddir and change _SOURCES?

If so, just need to force mkdir -p before the awk

[dorileo]

The patch indeed seems to fix the issue, but @barbieri do you mean not generating source code within the source tree but builddir instead?

[barbieri]

Yes

[Tarnyko]

@barbieri Good point, few time left at the moment, will look at it next week.