ENH: Clarified documentation of DEFINE_SYMBOL.

Source/cmSetTargetPropertiesCommand.h

@@ -61,8 +61,8 @@ public:
         "Properties that cmake knows about are PREFIX and SUFFIX for UNIX "
         "systems and libraries.   CMake also knows about LINK_FLAGS, which "
         "can be used to add extra flags to the link step of a target. "
-        "DEFINE_SYMBOL is a symbol that is defined when compiling C or C++ "
-        "sources. "
+        "DEFINE_SYMBOL sets the name of the preprocessor symbol defined when "
+        "compiling sources in a shared library. "
         "If not set here then it is set to target_EXPORTS by default "
         "(with some substitutions if the target is not a valid C "
         "identifier). "