Don't exit from pyproject-srpm-macros implementation of %pyproject_buildrequires

- Fixes: rhbz#2391290

Consider code like this:

    %generate_buildrequires
    mv setup.py{,.ignore}
    %pyproject_buildrequires
    mv setup.py{.ignore,}

When %pyproject_buildrequires exits, the second mv is never executed.
The next round of %generate_buildrequires will then fail.

In fact, there is probably not a good reason to call exit from %pyproject_buildrequires.

From https://src.fedoraproject.org/rpms/libcpuid/pull-request/7

(cherry picked from Fedora commit ea56d1c870)

macros.aaa-pyproject-srpm

@@ -4,7 +4,7 @@
 # this macro will cause the package with the real macro to be installed.
 # When macros.pyproject is installed, it overrides this macro.
 # Note: This takes arbitrary options, to ease addition of new options to the real macro.
-%pyproject_buildrequires(-) echo 'pyproject-rpm-macros' && exit 0
+%pyproject_buildrequires(-) echo 'pyproject-rpm-macros'
 
 
 # Declarative buildsystem, requires RPM 4.20+ to work

pyproject-rpm-macros.spec

@@ -14,8 +14,8 @@ License:        MIT
 #   Increment Y and reset Z when new macros or features are added
 #   Increment Z when this is a bugfix or a cosmetic change
 # Dropping support for EOL Fedoras is *not* considered a breaking change
-Version:        1.18.3
-Release:        2%{?dist}
+Version:        1.18.4
+Release:        1%{?dist}
 
 # Macro files
 Source001:      macros.pyproject
@@ -191,6 +191,10 @@ export HOSTNAME="rpmbuild"  # to speedup tox in network-less mock, see rhbz#1856
 
 
 %changelog
+* Mon Sep 01 2025 Miro Hrončok <mhroncok@redhat.com> - 1.18.4-1
+- Don't exit from pyproject-srpm-macros implementation of %%pyproject_buildrequires
+- Fixes: rhbz#2391290
+
 * Fri Jul 25 2025 Fedora Release Engineering <releng@fedoraproject.org> - 1.18.3-2
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_43_Mass_Rebuild