Build of pygraphviz failed with SWIG 4.2.0

[jplesnik]

The build of python-pygraphviz-1.11 is failing against SWIG 4.2.0 in Fedora rawhide/40.

pygraphviz/graphviz_wrap.c: In function ‘SWIG_AsCharPtrAndSize’:
pygraphviz/graphviz_wrap.c:3255:17: error: implicit declaration of function ‘SWIG_Python_str_AsChar’; did you mean ‘SWIG_Python_str_FromChar’? [-Wimplicit-function-declaration]
 3255 |         *cptr = SWIG_Python_str_AsChar(obj);
      |                 ^~~~~~~~~~~~~~~~~~~~~~
      |                 SWIG_Python_str_FromChar
pygraphviz/graphviz_wrap.c:3255:15: error: assignment to ‘char *’ from ‘int’ makes pointer from integer without a cast [-Wint-conversion]
 3255 |         *cptr = SWIG_Python_str_AsChar(obj);
      |               ^
error: command '/usr/bin/gcc' failed with exit code 1

Complete build log is here. Other information about the build can be found here.

[ojwb]

This looks like further fallout from @wsfulton's changes.

[wsfulton]

pygraphviz has an ancient outdated copy of pystrings.swg as an override to SWIG's version. pygraphviz/pygraphviz#508 should fix this and restore it to use the SWIG maintained version which of course doesn't have the SWIG_Python_str_AsChar problem.

[jplesnik]

@wsfulton The fix works for Fedora. Thank you