Options with parameters (like -INPUTCHARSET) for makensisw.exe are not parsed correctly. Parameters are treated as separate option and for example: "makensisw.exe -WX -INPUTCHARSET UTF8 -- somefile.nsi" ends up with error, that value for INPUTCHARSET is invalid, because makensisw treat "UTF8" as script file and cut following options.
This patch fixes this for "-INPUTCHARSET" and "-OUTPUTCHARSET", and also recognize "--" option. There is also /Xscriptcmd option, but as I understand, it will not be trivial to parse. I propose to rewrite processing options, so that all options specific to makensisw will be parsed first and removed from string, and rest of the string will be send to makensis without changes. That way makensisw would not need to even known about makensis options and it will work even when there will be added new options to makensis.