clang doesn't support -Wstrict-null-sentinel
clang warnings: assignments inside conditions should include parentheses
clang requires a push for every pop
clang: add default branch
clang: fix warning about converting integer enum to char pointer

warning: expression which evaluates to zero treated as a null pointer
constant of type 'const char *'
clang: add trailing newline to generated readme files
clang: fix wrong qualifiers

hidden overloaded virtual function 'std::exception::what'
declared here: different qualifiers (const vs none)
clang: assignments inside conditions should include parentheses
clang: add newline to end of file
clang: simply enable assert for testmod_ni.c

Since it's a testcase enabling assert does no harm
clang: replace latin1 chars with hex literals

fixes illegal character encoding in string literal
Simplify diagnostic pragmas
fix macro expansion
Merge pull request #112 from manuelm/clang

Fix clang warnings, closes #109