Simplify and add links in _DEBUG macro reference

Author: Rageking8

docs/c-runtime-library/debug.md

@@ -7,10 +7,11 @@ ms.assetid: a9901568-4846-4731-a404-399d947e2e7a
 ---
 # `_DEBUG`
 
-The compiler defines `_DEBUG` when you specify the `/MTd`, `/MDd`, or `/LDd` option. These options specify debug versions of the C run-time library.
+The compiler defines `_DEBUG` when you specify the [`/MTd`](../build/reference/md-mt-ld-use-run-time-library.md), [`/MDd`](../build/reference/md-mt-ld-use-run-time-library.md), or [`/LDd`](../build/reference/md-mt-ld-use-run-time-library.md) option. These options specify debug versions of the C run-time library.
 
-For more information, see [CRT debugging techniques](./crt-debugging-techniques.md).
+For more information, see [CRT debugging techniques](crt-debugging-techniques.md).
 
 ## See also
 
-[Control flags](./control-flags.md)
+[Control flags](control-flags.md)\
+[Predefined macros](../preprocessor/predefined-macros.md)