The compiler flag has been added to CFLAGS_NODIST and
LDFLAGS_NODIST. This will compile the core interpreter
and the stdlib modules with -fno-semantic-interposition
but will not affect user build and rpm C extension modules
compiled by distutils.
This has the effect of speeding up the interpreter up to
27%, depending on the workload, with the drawback of disabling
the capability of using LD_PRELOAD to override symbols in
libpython.
https://fedoraproject.org/wiki/Changes/PythonNoSemanticInterpositionSpeedup
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