When no shared library is installed, the new code to determine the name
of the -gdb.py file yields an empty string. Use the name of the static
library in that case.

libstdc++-v3/ChangeLog:

	PR libstdc++/99453
	* python/Makefile.am: Use archive name for printer hook if no
	dynamic library name is available.
	* python/Makefile.in: Regenerate.

Tested x86_64-linux. Committed to trunk. This is needed for gcc-11
too.