Hello,
I encountered errors when building rpm on fedora33:

Versions:
libvirt: v6.9.0-rc2
gcc-10.2.1-5.fc33.x86_64
meson-0.55.3-1.fc33.noarch
ninja-build-1.10.1-2.fc33.x86_64
binutils-2.35-11.fc33.x86_64

Steps:
1. Archive libvirt source code to ~/rpmbuild/SOURCES/libvirt-6.9.0.tar.xz
2. Copy libvirt.spec.in to ~/rpmbuild/SPECS/libvirt.spec. Then `sed -i s/@VERSION@/6.9.0/g ~/rpmbuild/SPECS/libvirt.spec`
3. Build rpm:
$ rpmbuild -ba ~/rpmbuild/SPECS/libvirt.spec

Then errors happen:
[1071/1255] gcc  -o tests/qemucapsprobe tests/qemucapsprobe.p/qemucapsprobe.c.o -Wl,--as-needed -Wl,--no-undefined -Wl,-export-dynamic -pie -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -Wl,--start-group tests/libtest_qemu_driver.so src/libvirt.so.0.6009.0 -Wl,-export-dynamic -ldl /usr/lib64/libglib-2.0.so /usr/lib64/libgobject-2.0.so /usr/lib64/libgio-2.0.so /usr/lib64/libgnutls.so /usr/lib64/libnl-3.so /usr/lib64/libnl-route-3.so /usr/lib64/libxml2.so /usr/lib64/libsasl2.so -lselinux /usr/lib64/libtirpc.so /usr/lib64/libyajl.so -Wl,--end-group '-Wl,-rpath,$ORIGIN/:$ORIGIN/../src' -Wl,-rpath-link,/home/hhan/rpmbuild/BUILD/libvirt-6.9.0/x86_64-redhat-linux-gnu/tests -Wl,-rpath-link,/home/hhan/rpmbuild/BUILD/libvirt-6.9.0/x86_64-redhat-linux-gnu/src
FAILED: tests/qemucapsprobe
gcc  -o tests/qemucapsprobe tests/qemucapsprobe.p/qemucapsprobe.c.o -Wl,--as-needed -Wl,--no-undefined -Wl,-export-dynamic -pie -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -Wl,--start-group tests/libtest_qemu_driver.so src/libvirt.so.0.6009.0 -Wl,-export-dynamic -ldl /usr/lib64/libglib-2.0.so /usr/lib64/libgobject-2.0.so /usr/lib64/libgio-2.0.so /usr/lib64/libgnutls.so /usr/lib64/libnl-3.so /usr/lib64/libnl-route-3.so /usr/lib64/libxml2.so /usr/lib64/libsasl2.so -lselinux /usr/lib64/libtirpc.so /usr/lib64/libyajl.so -Wl,--end-group '-Wl,-rpath,$ORIGIN/:$ORIGIN/../src' -Wl,-rpath-link,/home/hhan/rpmbuild/BUILD/libvirt-6.9.0/x86_64-redhat-linux-gnu/tests -Wl,-rpath-link,/home/hhan/rpmbuild/BUILD/libvirt-6.9.0/x86_64-redhat-linux-gnu/src
/usr/bin/ld: tests/libtest_qemu_driver.so: undefined reference to `__open_missing_mode'
collect2: error: ld returned 1 exit status
[1072/1255] gcc  -o tests/virtimetest src/libvirt_probes.o tests/virtimetest.p/virtimetest.c.o -Wl,--as-needed -Wl,--no-undefined -Wl,-export-dynamic -pie -Wl,--whole-archive -Wl,--start-group tests/libtest_utils.a -Wl,--no-whole-archive -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld src/libvirt.so.0.6009.0 -Wl,--no-copy-dt-needed-entries -Wl,-export-dynamic -ldl /usr/lib64/libglib-2.0.so /usr/lib64/libgobject-2.0.so /usr/lib64/libgio-2.0.so /usr/lib64/libgnutls.so /usr/lib64/libnl-3.so /usr/lib64/libnl-route-3.so /usr/lib64/libxml2.so /usr/lib64/libsasl2.so -lselinux /usr/lib64/libtirpc.so /usr/lib64/libyajl.so -Wl,-export-dynamic -lselinux -Wl,--end-group '-Wl,-rpath,$ORIGIN/../src' -Wl,-rpath-link,/home/hhan/rpmbuild/BUILD/libvirt-6.9.0/x86_64-redhat-linux-gnu/src
[1073/1255] gcc  -o tests/virstringtest src/libvirt_probes.o tests/virstringtest.p/virstringtest.c.o -Wl,--as-needed -Wl,--no-undefined -Wl,-export-dynamic -pie -Wl,--whole-archive -Wl,--start-group tests/libtest_utils.a -Wl,--no-whole-archive -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld src/libvirt.so.0.6009.0 -Wl,--no-copy-dt-needed-entries -Wl,-export-dynamic -ldl /usr/lib64/libglib-2.0.so /usr/lib64/libgobject-2.0.so /usr/lib64/libgio-2.0.so /usr/lib64/libgnutls.so /usr/lib64/libnl-3.so /usr/lib64/libnl-route-3.so /usr/lib64/libxml2.so /usr/lib64/libsasl2.so -lselinux /usr/lib64/libtirpc.so /usr/lib64/libyajl.so -Wl,-export-dynamic -lselinux -Wl,--end-group '-Wl,-rpath,$ORIGIN/../src' -Wl,-rpath-link,/home/hhan/rpmbuild/BUILD/libvirt-6.9.0/x86_64-redhat-linux-gnu/src
[1074/1255] gcc  -o tests/virsystemdtest src/libvirt_probes.o tests/virsystemdtest.p/virsystemdtest.c.o -Wl,--as-needed -Wl,--no-undefined -Wl,-export-dynamic -pie -Wl,--whole-archive -Wl,--start-group tests/libtest_utils.a -Wl,--no-whole-archive -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld src/libvirt.so.0.6009.0 -Wl,--no-copy-dt-needed-entries -Wl,-export-dynamic -ldl /usr/lib64/libglib-2.0.so /usr/lib64/libgobject-2.0.so /usr/lib64/libgio-2.0.so /usr/lib64/libgnutls.so /usr/lib64/libnl-3.so /usr/lib64/libnl-route-3.so /usr/lib64/libxml2.so /usr/lib64/libsasl2.so -lselinux /usr/lib64/libtirpc.so /usr/lib64/libyajl.so -Wl,-export-dynamic -lselinux -Wl,--end-group '-Wl,-rpath,$ORIGIN/../src' -Wl,-rpath-link,/home/hhan/rpmbuild/BUILD/libvirt-6.9.0/x86_64-redhat-linux-gnu/src
[1075/1255] gcc  -o tests/virtypedparamtest src/libvirt_probes.o tests/virtypedparamtest.p/virtypedparamtest.c.o -Wl,--as-needed -Wl,--no-undefined -Wl,-export-dynamic -pie -Wl,--whole-archive -Wl,--start-group tests/libtest_utils.a -Wl,--no-whole-archive -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld src/libvirt.so.0.6009.0 -Wl,--no-copy-dt-needed-entries -Wl,-export-dynamic -ldl /usr/lib64/libglib-2.0.so /usr/lib64/libgobject-2.0.so /usr/lib64/libgio-2.0.so /usr/lib64/libgnutls.so /usr/lib64/libnl-3.so /usr/lib64/libnl-route-3.so /usr/lib64/libxml2.so /usr/lib64/libsasl2.so -lselinux /usr/lib64/libtirpc.so /usr/lib64/libyajl.so -Wl,-export-dynamic -lselinux -Wl,--end-group '-Wl,-rpath,$ORIGIN/../src' -Wl,-rpath-link,/home/hhan/rpmbuild/BUILD/libvirt-6.9.0/x86_64-redhat-linux-gnu/src
[1076/1255] gcc  -o tests/domaincapstest src/libvirt_probes.o tests/domaincapstest.p/domaincapstest.c.o -Wl,--as-needed -Wl,--no-undefined -Wl,-export-dynamic -pie -Wl,--whole-archive -Wl,--start-group tests/libtest_utils.a tests/libtest_file_wrapper.a tests/libtest_utils_xen.a tests/libtest_utils_qemu.a -Wl,--no-whole-archive -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld src/libvirt.so.0.6009.0 tests/libtest_xen_driver.so tests/libtest_qemu_driver.so -Wl,--no-copy-dt-needed-entries -Wl,-export-dynamic -ldl /usr/lib64/libglib-2.0.so /usr/lib64/libgobject-2.0.so /usr/lib64/libgio-2.0.so /usr/lib64/libgnutls.so /usr/lib64/libnl-3.so /usr/lib64/libnl-route-3.so /usr/lib64/libxml2.so /usr/lib64/libsasl2.so -lselinux /usr/lib64/libtirpc.so /usr/lib64/libyajl.so -Wl,-export-dynamic -lselinux -Wl,-export-dynamic -lselinux -Wl,-export-dynamic -lselinux -Wl,-export-dynamic -lselinux -Wl,--end-group '-Wl,-rpath,$ORIGIN/../src:$ORIGIN/' -Wl,-rpath-link,/home/hhan/rpmbuild/BUILD/libvirt-6.9.0/x86_64-redhat-linux-gnu/src -Wl,-rpath-link,/home/hhan/rpmbuild/BUILD/libvirt-6.9.0/x86_64-redhat-linux-gnu/tests
FAILED: tests/domaincapstest
gcc  -o tests/domaincapstest src/libvirt_probes.o tests/domaincapstest.p/domaincapstest.c.o -Wl,--as-needed -Wl,--no-undefined -Wl,-export-dynamic -pie -Wl,--whole-archive -Wl,--start-group tests/libtest_utils.a tests/libtest_file_wrapper.a tests/libtest_utils_xen.a tests/libtest_utils_qemu.a -Wl,--no-whole-archive -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld src/libvirt.so.0.6009.0 tests/libtest_xen_driver.so tests/libtest_qemu_driver.so -Wl,--no-copy-dt-needed-entries -Wl,-export-dynamic -ldl /usr/lib64/libglib-2.0.so /usr/lib64/libgobject-2.0.so /usr/lib64/libgio-2.0.so /usr/lib64/libgnutls.so /usr/lib64/libnl-3.so /usr/lib64/libnl-route-3.so /usr/lib64/libxml2.so /usr/lib64/libsasl2.so -lselinux /usr/lib64/libtirpc.so /usr/lib64/libyajl.so -Wl,-export-dynamic -lselinux -Wl,-export-dynamic -lselinux -Wl,-export-dynamic -lselinux -Wl,-export-dynamic -lselinux -Wl,--end-group '-Wl,-rpath,$ORIGIN/../src:$ORIGIN/' -Wl,-rpath-link,/home/hhan/rpmbuild/BUILD/libvirt-6.9.0/x86_64-redhat-linux-gnu/src -Wl,-rpath-link,/home/hhan/rpmbuild/BUILD/libvirt-6.9.0/x86_64-redhat-linux-gnu/tests
/usr/bin/ld: tests/libtest_qemu_driver.so: undefined reference to `__open_missing_mode'
collect2: error: ld returned 1 exit status
[1077/1255] gcc  -o tests/vircapstest src/qemu/libvirt_qemu_probes.o src/libvirt_probes.o tests/vircapstest.p/vircapstest.c.o -Wl,--as-needed -Wl,--no-undefined -Wl,-export-dynamic -pie -Wl,--whole-archive -Wl,--start-group tests/libtest_utils.a tests/libtest_utils_lxc.a tests/libtest_utils_qemu.a -Wl,--no-whole-archive -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld src/libvirt.so.0.6009.0 src/lxc/libvirt_driver_lxc_impl.a src/qemu/libvirt_driver_qemu_impl.a -Wl,--no-copy-dt-needed-entries -Wl,-export-dynamic -ldl /usr/lib64/libglib-2.0.so /usr/lib64/libgobject-2.0.so /usr/lib64/libgio-2.0.so /usr/lib64/libgnutls.so /usr/lib64/libnl-3.so /usr/lib64/libnl-route-3.so /usr/lib64/libxml2.so /usr/lib64/libsasl2.so -lselinux /usr/lib64/libtirpc.so /usr/lib64/libyajl.so /usr/lib64/libblkid.so -lcap-ng /usr/lib64/libfuse.so -pthread -lselinux -Wl,-z,relro -Wl,-z,now -Wl,--no-copy-dt-needed-entries -Wl,-export-dynamic -lcap-ng -lselinux -Wl,-z,relro -Wl,-z,now -Wl,--no-copy-dt-needed-entries -Wl,-export-dynamic -Wl,-export-dynamic -lselinux -Wl,-export-dynamic -lselinux -Wl,-export-dynamic -lselinux -Wl,--end-group '-Wl,-rpath,$ORIGIN/../src' -Wl,-rpath-link,/home/hhan/rpmbuild/BUILD/libvirt-6.9.0/x86_64-redhat-linux-gnu/src
[1078/1255] gcc  -o tests/cputest src/libvirt_probes.o tests/cputest.p/cputest.c.o -Wl,--as-needed -Wl,--no-undefined -Wl,-export-dynamic -pie -Wl,--whole-archive -Wl,--start-group tests/libtest_utils.a tests/libtest_utils_qemu.a -Wl,--no-whole-archive -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld src/libvirt.so.0.6009.0 tests/libtest_utils_qemu_monitor.a tests/libtest_qemu_driver.so -Wl,--no-copy-dt-needed-entries -Wl,-export-dynamic -ldl /usr/lib64/libglib-2.0.so /usr/lib64/libgobject-2.0.so /usr/lib64/libgio-2.0.so /usr/lib64/libgnutls.so /usr/lib64/libnl-3.so /usr/lib64/libnl-route-3.so /usr/lib64/libxml2.so /usr/lib64/libsasl2.so -lselinux /usr/lib64/libtirpc.so /usr/lib64/libyajl.so -Wl,-export-dynamic -lselinux -Wl,-export-dynamic -lselinux -Wl,-export-dynamic -lselinux -Wl,--end-group '-Wl,-rpath,$ORIGIN/../src:$ORIGIN/' -Wl,-rpath-link,/home/hhan/rpmbuild/BUILD/libvirt-6.9.0/x86_64-redhat-linux-gnu/src -Wl,-rpath-link,/home/hhan/rpmbuild/BUILD/libvirt-6.9.0/x86_64-redhat-linux-gnu/tests
FAILED: tests/cputest
gcc  -o tests/cputest src/libvirt_probes.o tests/cputest.p/cputest.c.o -Wl,--as-needed -Wl,--no-undefined -Wl,-export-dynamic -pie -Wl,--whole-archive -Wl,--start-group tests/libtest_utils.a tests/libtest_utils_qemu.a -Wl,--no-whole-archive -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld src/libvirt.so.0.6009.0 tests/libtest_utils_qemu_monitor.a tests/libtest_qemu_driver.so -Wl,--no-copy-dt-needed-entries -Wl,-export-dynamic -ldl /usr/lib64/libglib-2.0.so /usr/lib64/libgobject-2.0.so /usr/lib64/libgio-2.0.so /usr/lib64/libgnutls.so /usr/lib64/libnl-3.so /usr/lib64/libnl-route-3.so /usr/lib64/libxml2.so /usr/lib64/libsasl2.so -lselinux /usr/lib64/libtirpc.so /usr/lib64/libyajl.so -Wl,-export-dynamic -lselinux -Wl,-export-dynamic -lselinux -Wl,-export-dynamic -lselinux -Wl,--end-group '-Wl,-rpath,$ORIGIN/../src:$ORIGIN/' -Wl,-rpath-link,/home/hhan/rpmbuild/BUILD/libvirt-6.9.0/x86_64-redhat-linux-gnu/src -Wl,-rpath-link,/home/hhan/rpmbuild/BUILD/libvirt-6.9.0/x86_64-redhat-linux-gnu/tests
/usr/bin/ld: tests/libtest_qemu_driver.so: undefined reference to `__open_missing_mode'
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.
error: Bad exit status from /var/tmp/rpm-tmp.xEqkEF (%build)


RPM build errors:
    Bad exit status from /var/tmp/rpm-tmp.xEqkEF (%build)