<xsd:attribute name="Compiler" type="xsd:string" use="optional" default="gcc"/>
          <xsd:attribute name="CFLAGS" type="xsd:string" use="required"/>
          <xsd:attribute name="Linker" type="xsd:string" use="optional" default="ld"/>
          <xsd:attribute name="LDFLAGS" type="xsd:string" use="required"/>