bpo-32197: Try to fix a compiler error introduced in bpo-32030.

[serhiy-storchaka]

https://bugs.python.org/issue32197

[ambv]

Why -1? Does the return matter?

[ned-deily]

On macOS:

../../source/Modules/main.c:904:13: error: use of undeclared identifier 'pymain'
            SET_DECODE_ERROR("PYTHONEXECUTABLE environment variable", len);
            ^
../../source/Modules/main.c:48:13: note: expanded from macro 'SET_DECODE_ERROR'
            pymain->err = _Py_INIT_USER_ERR("cannot decode " #NAME); \
            ^
../../source/Modules/main.c:904:13: error: use of undeclared identifier 'pymain'
../../source/Modules/main.c:51:13: note: expanded from macro 'SET_DECODE_ERROR'
            pymain->err = _Py_INIT_NO_MEMORY(); \
            ^
../../source/Modules/main.c:905:20: error: returning 'int' from a function with incompatible result type '_PyInitError'
            return -1;
                   ^~
../../source/Modules/main.c:919:17: error: use of undeclared identifier 'pymain'
                SET_DECODE_ERROR("__PYVENV_LAUNCHER__ environment variable",
                ^
../../source/Modules/main.c:48:13: note: expanded from macro 'SET_DECODE_ERROR'
            pymain->err = _Py_INIT_USER_ERR("cannot decode " #NAME); \
            ^
../../source/Modules/main.c:919:17: error: use of undeclared identifier 'pymain'
../../source/Modules/main.c:51:13: note: expanded from macro 'SET_DECODE_ERROR'
            pymain->err = _Py_INIT_NO_MEMORY(); \
            ^
../../source/Modules/main.c:921:24: error: returning 'int' from a function with incompatible result type '_PyInitError'
                return -1;

[serhiy-storchaka]

My attempt failed.