Description of problem:
Package libzypp fails to build from source in Fedora Rawhide.

Version-Release number of selected component (if applicable):
17.31.8-2.fc39

Steps to Reproduce:
koji build --scratch f39 libzypp-17.31.8-2.fc39.src.rpm

Additional info:
This package is tracked by Koschei. See:
https://koschei.fedoraproject.org/package/libzypp

----

In file included from /builddir/build/BUILD/libzypp-17.31.8/zypp-curl/proxyinfo/ProxyInfoLibproxy:1,
                 from /builddir/build/BUILD/libzypp-17.31.8/zypp-curl/proxyinfo/proxyinfos.h:20,
                 from /builddir/build/BUILD/libzypp-17.31.8/zypp-curl/proxyinfo.cc:19:
/builddir/build/BUILD/libzypp-17.31.8/zypp-curl/proxyinfo/proxyinfolibproxy.h:18:10: fatal error: proxy.h: No such file or directory
   18 | #include <proxy.h>
      |          ^~~~~~~~~


Reproducible: Always

Steps to Reproduce:
1. fedpkg co libzypp
2. cd libzypp
3. fedpkg mockbuild
Actual Results:  
Build fails due to missing proxy.h.

Expected Results:  
Successful build.

Discovered while checking impact of https://src.fedoraproject.org/rpms/protobuf/pull-request/25.