test_curses reference leak in the Python main branch

[vstinner]

At commit e925241, test_curses leaks references:

$ ./python -m test test_curses -m test_output_string_embedded_null_chars -u all  -R 3:3
(...)
test_curses leaked [4, 4, 4] references, sum=12

I reproduce the issue on Fedora.

Example of failing buildbot: https://buildbot.python.org/all/#/builders/16/builds/244

Before this change, Python doesn't leak references.

Before: make:

gcc -fPIC -g -Og -Wall -O0 -std=c11 -Werror=implicit-function-declaration -fvisibility=hidden -I./Include/internal -DHAVE_NCURSESW=1 -I/usr/include/ncursesw -I./Include -I. -I/usr/local/include -I/home/vstinner/python/main/Include -I/home/vstinner/python/main -c /home/vstinner/python/main/Modules/_cursesmodule.c -o build/temp.linux-x86_64-3.12-pydebug/home/vstinner/python/main/Modules/_cursesmodule.o

gcc -fPIC -g -Og -Wall -O0 -std=c11 -Werror=implicit-function-declaration -fvisibility=hidden -I./Include/internal -DHAVE_NCURSESW=1 -I/usr/include/ncursesw -I./Include -I. -I/usr/local/include -I/home/vstinner/python/main/Include -I/home/vstinner/python/main -c /home/vstinner/python/main/Modules/_curses_panel.c -o build/temp.linux-x86_64-3.12-pydebug/home/vstinner/python/main/Modules/_curses_panel.o

After: make:

gcc -fPIC -g -Og -Wall -O0 -std=c11 -Werror=implicit-function-declaration -fvisibility=hidden -I./Include/internal -D_DEFAULT_SOURCE -I./Include -I. -I/usr/local/include -I/home/vstinner/python/main/Include -I/home/vstinner/python/main -c /home/vstinner/python/main/Modules/_cursesmodule.c -o build/temp.linux-x86_64-3.12-pydebug/home/vstinner/python/main/Modules/_cursesmodule.o

gcc -fPIC -g -Og -Wall -O0 -std=c11 -Werror=implicit-function-declaration -fvisibility=hidden -I./Include/internal -D_DEFAULT_SOURCE -D_XOPEN_SOURCE=600 -D_DEFAULT_SOURCE -I./Include -I. -I/usr/local/include -I/home/vstinner/python/main/Include -I/home/vstinner/python/main -c /home/vstinner/python/main/Modules/_curses_panel.c -o build/temp.linux-x86_64-3.12-pydebug/home/vstinner/python/main/Modules/_curses_panel.o

The commit removes -DHAVE_NCURSESW=1 -I/usr/include/ncursesw options and adds -D_DEFAULT_SOURCE option to the (gcc) build command line of the _curses extension.

cc @tiran @erlend-aasland

[tiran]

HAVE_NCURSESW should be added to pyconfig.h. The pkg-config branch does not define the config value.

The problem may have revealed an old bug in the non-wide curses build.

[tiran]

@kumaraditya303 fixed the reference leak when the curses module is built without ncursesw. I addressed the missing HAVE_NCURSESW in the pkg-config branch. Additional defines and include directories are now coming from pkg-config or env var overrides.