added wno_writable_strings to warning ignores (so it stops complaining at constexpr arrays of char*). also moved from c++14 to c++17 (-std=c++1z)
added wno_writable_strings to warning ignores (so it stops complaining at constexpr arrays of char*). also moved from c++14 to c++17 (-std=c++1z)

mflagel/asdf_multiplat,mflagel/asdf_multiplat,mflagel/asdf_multiplat