Convert builtin help to reStructuredText source files

Run the convert-help.bash script to convert documentation:

 ./convert-help.bash "/path/to/CMake-build/bin"

Then remove it.

Help/variable/CMAKE_LINK_DEF_FILE_FLAG.rst

@@ -0,0 +1,7 @@
+CMAKE_LINK_DEF_FILE_FLAG
+------------------------
+
+Linker flag to be used to specify a .def file for dll creation.
+
+The flag will be used to add a .def file when creating a dll on
+Windows; this is only defined on Windows.