Add prebuilt bindings for GDAL 3.6 and document how to do it

Fixes #351

CHANGES.md

@@ -14,6 +14,8 @@
 
   - <https://github.com/georust/gdal/pull/347>
 
+- Added prebuilt bindings for GDAL 3.6 (released 6 November 2022).
+
 ## 0.14
 
 - Added new content to `README.md` and the root docs.

gdal-sys/Readme.md

@@ -37,3 +37,12 @@ attempt to use prebuilt bindings corresponding to that version. Alternatively,
 you can generate your own bindings from your libgdal installation by specifying
 the `bindgen` feature.
 
+## Creating prebuilt bindings
+
+If a new version of GDAL is released, you (as a `gdal` contributor) can
+generate new bindings for inclusion in the `gdal-sys` source distribution by
+building with the `bindgen` feature, and then copying the generated file. For
+example (the hash will differ in your build):
+
+    $ cargo build --features bindgen
+    $ cp target/debug/build/gdal-sys-db833e3088b78e57/out/bindings.rs gdal-sys/prebuilt-bindings/gdal_3.6.rs

gdal-sys/build.rs

@@ -22,8 +22,10 @@ pub fn write_bindings(include_paths: Vec<String>, out_path: &Path) {
         .allowlist_function("VSI.*");
 
     for path in include_paths {
-        builder = builder.clang_arg("-I");
-        builder = builder.clang_arg(path);
+        builder = builder
+            .clang_arg("-I")
+            .clang_arg(path)
+            .clang_arg("-fretain-comments-from-system-headers");
     }
 
     builder