def to_string_list(self, sourcedir: str, builddir: str) -> T.List[str]:
        """Convert IncludeDirs object to a list of strings.

        :param sourcedir: The absolute source directory
        :param builddir: The absolute build directory, option, build dir will not
            be added if this is unset
        :returns: A list of strings (without compiler argument)
        """
        strlist: T.List[str] = []
        for idir in self.incdirs:
            strlist.append(os.path.join(sourcedir, self.curdir, idir))
            strlist.append(os.path.join(builddir, self.curdir, idir))
        return strlist
Convert IncludeDirs object to a list of strings.

        :param sourcedir: The absolute source directory
        :param builddir: The absolute build directory, option, build dir will not
            be added if this is unset
        :returns: A list of strings (without compiler argument)
        
mesonbuild/build.py