docs: Document conditional debug compilation flags [skip ci]

1 files changed, 8 insertions, 2 deletions

diff --git a/docs/markdown/D.md b/docs/markdown/D.md
index 15de2f7..2b0eaac 100644
--- a/docs/markdown/D.md
+++ b/docs/markdown/D.md
@@ -14,15 +14,21 @@ project('myapp', 'd')
 executable('myapp', 'app.d')
 ```
 
-## Compiling different versions
+## [Conditional compilation](https://dlang.org/spec/version.html)
 
-If you are using the [version()](https://dlang.org/spec/version.html) feature for conditional compilation,
+If you are using the [version()](https://dlang.org/spec/version.html#version-specification) feature for conditional compilation,
 you can use it using the `d_module_versions` target property:
 ```meson
 project('myapp', 'd')
 executable('myapp', 'app.d', d_module_versions: ['Demo', 'FeatureA'])
 ```
 
+For debugging, [debug()](https://dlang.org/spec/version.html#debug) conditions are compiled automatically in debug builds, and extra identifiers can be added with the `d_debug` argument:
+```meson
+project('myapp', 'd')
+executable('myapp', 'app.d', d_debug: [3, 'DebugFeatureA'])
+```
+
 ## Using embedded unittests
 
 If you are using embedded [unittest functions](https://dlang.org/spec/unittest.html), your source code needs