ENH: add support for xlf with -WF,-D for -D

Modules/Platform/AIX-VisualAge-Fortran.cmake

@@ -0,0 +1 @@
+include(Platforms/xlf)

Modules/Platform/Linux-VisualAge-Fortran.cmake

@@ -1,2 +1,3 @@
 SET(CMAKE_SHARED_LIBRARY_C_FLAGS "")        
 SET(CMAKE_SHARED_LIBRARY_LINK_C_FLAGS "")  
+include(Platforms/xlf)

Modules/Platform/xlf.cmake

@@ -0,0 +1 @@
+set(CMAKE_DEFINE_FLAG_Fortran "-WF,-D")