gdb fails to build with Python 3.9.0a5.

g++ -x c++  -O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection  -DDNF_DEBUGINFO_INSTALL   -I. -I../../gdb -I../../gdb/config -DLOCALEDIR="\"/usr/share/locale\"" -DHAVE_CONFIG_H -I../../gdb/../include/opcode   -I../bfd -I../../gdb/../bfd -I../../gdb/../include -I../libdecnumber -I../../gdb/../libdecnumber  -I../../gdb/../gnulib/import -I../gnulib/import  -DTUI=1    -I/usr/include/guile/2.0 -pthread  -I/usr/include/python3.9 -I/usr/include/python3.9  -I../../gdb/.. -pthread -Wall -Wpointer-arith -Wno-unused -Wunused-value -Wunused-variable -Wunused-function -Wno-switch -Wno-char-subscripts -Wempty-body -Wunused-but-set-parameter -Wunused-but-set-variable -Wno-sign-compare -Wno-error=maybe-uninitialized -Wno-mismatched-tags -Wsuggest-override -Wimplicit-fallthrough=3 -Wduplicated-cond -Wshadow=local -Wdeprecated-copy -Wdeprecated-copy-dtor -Wredundant-move -Wformat -Wformat-nonliteral -Wno-unused -Werror -fno-strict-aliasing -fwrapv -DNDEBUG -c -o python/python.o -MT python/python.o -MMD -MP -MF python/.deps/python.Tpo ../../gdb/python/python.c
../../gdb/python/python.c: In function 'bool do_start_initialization()':
../../gdb/python/python.c:1621:23: error: 'void PyEval_InitThreads()' is deprecated [-Werror=deprecated-declarations]
 1621 |   PyEval_InitThreads ();
      |                       ^
In file included from /usr/include/python3.9/Python.h:141,
                 from ../../gdb/python/python-internal.h:86,
                 from ../../gdb/python/python.c:92:
/usr/include/python3.9/ceval.h:132:37: note: declared here
  132 | Py_DEPRECATED(3.9) PyAPI_FUNC(void) PyEval_InitThreads(void);
      |                                     ^~~~~~~~~~~~~~~~~~
g++ -x c++  -O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection  -DDNF_DEBUGINFO_INSTALL   -I. -I../../gdb -I../../gdb/config -DLOCALEDIR="\"/usr/share/locale\"" -DHAVE_CONFIG_H -I../../gdb/../include/opcode   -I../bfd -I../../gdb/../bfd -I../../gdb/../include -I../libdecnumber -I../../gdb/../libdecnumber  -I../../gdb/../gnulib/import -I../gnulib/import  -DTUI=1    -I/usr/include/guile/2.0 -pthread  -I/usr/include/python3.9 -I/usr/include/python3.9  -I../../gdb/.. -pthread -Wall -Wpointer-arith -Wno-unused -Wunused-value -Wunused-variable -Wunused-function -Wno-switch -Wno-char-subscripts -Wempty-body -Wunused-but-set-parameter -Wunused-but-set-variable -Wno-sign-compare -Wno-error=maybe-uninitialized -Wno-mismatched-tags -Wsuggest-override -Wimplicit-fallthrough=3 -Wduplicated-cond -Wshadow=local -Wdeprecated-copy -Wdeprecated-copy-dtor -Wredundant-move -Wformat -Wformat-nonliteral -Wno-unused -Werror -c -o ravenscar-thread.o -MT ravenscar-thread.o -MMD -MP -MF ./.deps/ravenscar-thread.Tpo ../../gdb/ravenscar-thread.c
cc1plus: all warnings being treated as errors
make[2]: *** [Makefile:1660: python/python.o] Error 1


See https://docs.python.org/3.9/whatsnew/3.9.html#deprecated

"The PyEval_InitThreads() and PyEval_ThreadsInitialized() functions are now deprecated and will be removed in Python 3.11. Calling PyEval_InitThreads() now does nothing. The GIL is initialized by Py_Initialize() since Python 3.7."


For the build logs, see:
https://copr-be.cloud.fedoraproject.org/results/@python/python3.9/fedora-rawhide-x86_64/01333713-gdb/

For all our attempts to build gdb with Python 3.9, see:
https://copr.fedorainfracloud.org/coprs/g/python/python3.9/package/gdb/

Testing and mass rebuild of packages is happening in copr. You can follow these instructions to test locally in mock if your package builds with Python 3.9:
https://copr.fedorainfracloud.org/coprs/g/python/python3.9/

Let us know here if you have any questions.

Python 3.9 will be included in Fedora 33. To make that update smoother, we're building Fedora packages with early pre-releases of Python 3.9.
A build failure prevents us from testing all dependent packages (transitive [Build]Requires), so if this package is required a lot, it's important for us to get it fixed soon.
We'd appreciate help from the people who know this package best, but if you don't want to work on this now, let us know so we can try to work around it on our side.