Use -Wno-sign-compare on g++ 4.4.7

test/Jamfile.v2

@@ -21,6 +21,7 @@ project
 
     <toolset>gcc:<cxxflags>-Wno-long-long
     <toolset>gcc-4.4.7:<cxxflags>-Wno-strict-aliasing
+    <toolset>gcc-4.4.7:<cxxflags>-Wno-sign-compare
     <toolset>gcc:<warnings-as-errors>on
 
     <toolset>clang:<cxxflags>-Wno-long-long