doc: add a section documenting #preinclude (#17304)

doc/docs.md

@@ -196,6 +196,7 @@ by using any of the following commands in a terminal:
     * [C Declarations](#c-declarations)
     * [Export to shared library](#export-to-shared-library)
     * [Translating C to V](#translating-c-to-v)
+    * [Working around C issues](#working-around-c-issues)
 * [Other V Features](#other-v-features)
     * [Inline assembly](#inline-assembly)
     * [Hot code reloading](#hot-code-reloading)
@@ -6424,6 +6425,37 @@ Translating it to V gives you several advantages:
 - Cross-compilation becomes a lot easier. You don't have to worry about it at all.
 - No more build flags and include files either.
 
+### Working around C issues
+
+In some cases, C interop can be extremely difficult.
+One of these such cases is when headers conflict with each other.
+For example, V needs to include the Windows header libraries in order for your V binaries to work
+seamlessly across all platforms.
+
+However, since the Windows header libraries use extremely generic names such as `Rectangle`,
+this will cause a conflict if you wish to use C code that also has a name defined as `Rectangle`.
+
+For very specific cases like this, we have `#preinclude`.
+
+This will allow things to be configured before V adds in its built in libraries.
+
+Example usage:
+```v ignore
+// This will include before built in libraries are used.
+#preinclude "pre_include.h"
+// This will include after built in libraries are used.
+#include "include.h"
+```
+
+An example of what might be included in `pre_include.h`
+can be [found here](https://github.com/irishgreencitrus/raylib.v/blob/main/include/pre.h)
+
+This is an advanced feature, and will not be necessary
+outside of very specific cases with C interop,
+meaning it could cause more issues than it solves.
+
+Consider it last resort!
+
 ## Other V Features
 
 ### Inline assembly