bpo-36301: Fix _PyPreConfig_Read() compiler warning

[vstinner]

Initialize init_utf8_mode earlier to fix a compiler warning.

https://bugs.python.org/issue36301

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Example of warning seen on PR #12661:

https://dev.azure.com/Python/cpython/_build/results?buildId=40348

Python/preconfig.c:725:13: warning: variable 'init_utf8_mode' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized] if (_Py_INIT_FAILED(err)) { ^~~~~~~~~~~~~~~~~~~~ ./Include/cpython/coreconfig.h:37:5: note: expanded from macro '_Py_INIT_FAILED' (err.msg != NULL || err.exitcode != -1) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Python/preconfig.c:815:19: note: uninitialized use occurs here Py_UTF8Mode = init_utf8_mode ; ^~~~~~~~~~~~~~ Python/preconfig.c:725:9: note: remove the 'if' if its condition is always false if (_Py_INIT_FAILED(err)) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~ Python/preconfig.c:725:29: warning: variable 'init_utf8_mode' is used uninitialized whenever '||' condition is true [-Wsometimes-uninitialized] if (_Py_INIT_FAILED(err)) { ~~~~~~~~~~~~~~~~^~~~ ./Include/cpython/coreconfig.h:37:6: note: expanded from macro '_Py_INIT_FAILED' (err.msg != NULL || err.exitcode != -1) ^~~~~~~~~~~~~~~ Python/preconfig.c:815:19: note: uninitialized use occurs here Py_UTF8Mode = init_utf8_mode ; ^~~~~~~~~~~~~~ Python/preconfig.c:725:29: note: remove the '||' if its condition is always false if (_Py_INIT_FAILED(err)) { ^ Python/preconfig.c:730:5: note: variable 'init_utf8_mode' is declared here int init_utf8_mode = Py_UTF8Mode; ^ 2 warnings generated. 

[tirkarthi]

See also #12644 . Does this PR also fix the same issue ?

[vstinner]

See also #12644 . Does this PR also fix the same issue ?

Thanks. I missed this PR, thanks for the pointer. I closed this PR as well.