Bug#977533: pytorch: FTBFS with fmtlib 1.7.3
When rebuild your package with fmtlib from experimental, it FTBFS.
However it just fails when dpkg-gensymbols.
The symbols file you provided, contains internal API of fmtlib,
for example all `_ZN3fmt2v68internal`.
It doesn't make sense for pytorch to expose these info in its symbols
file. I suggest just removing these. And C++ symbols are just nightmare,
it's better just drop the symbols file.