Apply the semantic patch to catch all the places where we pass 'char' to
the <ctype.h> family of functions (isalpha() and friends, toupper(),
tolower()).
Using check_PROGRAMS would postpone compiling the binaries needed by
system tests until `make check` would be called. Since it's preferable
to invoke pytest directly to run the system test suite, compile these
binaries without installing them during `make all` instead by using
noinst_PROGRAMS.
This removes the need to use TESTS= make -e check hack invoked from
pytest to work around this issue.
