ENH: try and fix aix xlC with gcc

Modules/Platform/AIX.cmake

@@ -8,6 +8,8 @@ SET(CMAKE_SHARED_LIBRARY_LINK_C_FLAGS "-Wl,-brtl,-bexpall")  # +s, flag for exe
 IF(CMAKE_COMPILER_IS_GNUCXX) 
   SET(CMAKE_SHARED_LIBRARY_CREATE_CXX_FLAGS "-shared -Wl,-G")       # -shared
 ELSE(CMAKE_COMPILER_IS_GNUCXX) 
+  SET(CMAKE_SHARED_LIBRARY_CREATE_CXX_FLAGS "-G -Wl,-brtl")       # -shared
+  SET(CMAKE_SHARED_LIBRARY_LINK_CXX_FLAGS "-Wl,-brtl,-bexpall")  # +s, flag for exe link to use shared lib
   SET(CMAKE_SHARED_LIBRARY_CXX_FLAGS " ")
   SET(CMAKE_SHARED_MODULE_CXX_FLAGS  " ")
 ENDIF(CMAKE_COMPILER_IS_GNUCXX) 
@@ -16,6 +18,8 @@ ENDIF(CMAKE_COMPILER_IS_GNUCXX)
 IF(CMAKE_COMPILER_IS_GNUCC)
   SET(CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS "-shared -Wl,-G")       # -shared
 ELSE(CMAKE_COMPILER_IS_GNUCC)
+  SET(CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS "-G -Wl,-brtl")  # -shared
+  SET(CMAKE_SHARED_LIBRARY_LINK_C_FLAGS "-Wl,-brtl,-bexpall")  # +s, flag for exe link to use shared lib
   SET(CMAKE_SHARED_LIBRARY_C_FLAGS " ")
   SET(CMAKE_SHARED_MODULE_C_FLAGS  " ")
 ENDIF(CMAKE_COMPILER_IS_GNUCC)