Incorporate underscore check into definitions

Author: islas

CMakeLists.txt

@@ -831,6 +831,12 @@ else()
   list( APPEND PROJECT_COMPILE_DEFINITIONS_CONFCHECK FSEEK_OK )
 endif()
 
+if ( ${NOUNDERSCORE_SYMBOL} )
+  list( APPEND PROJECT_COMPILE_DEFINITIONS_CONFCHECK NOUNDERSCORE )
+elseif( ${UNDERSCORE_SYMBOL} )
+  list( APPEND PROJECT_COMPILE_DEFINITIONS_CONFCHECK UNDERSCORE )
+endif()
+
 # I don't believe these are used anymore...
 # $<$<BOOL:${MPI2_SUPPORT}>:MPI2_SUPPORT=$<BOOL:${MPI2_SUPPORT}>>
 # $<$<BOOL:${MPI2_THREAD_SUPPORT}>:MPI2_THREAD_SUPPORT=$<BOOL:${MPI2_THREAD_SUPPORT}>>