Turn on EXPORT_COMPILE_COMMANDS

For `clangd` to work properly, one may need to make symbolic links

```
cd patch-loader
ln -sf $PWD/build/tools/debug/arm64-v8a/compile_commands.json build
```

.gitignore

@@ -1,4 +1,5 @@
 .project
+.cache
 .settings
 libxposed
 *.iml

build.gradle.kts

@@ -82,6 +82,7 @@ fun Project.configureBaseExtension() {
 
         externalNativeBuild.cmake {
             version = "3.28.1+"
+            buildStagingDirectory = layout.buildDirectory.get().asFile
         }
 
         defaultConfig {
@@ -122,6 +123,7 @@ fun Project.configureBaseExtension() {
                     cppFlags("-std=c++20", *flags)
                     cFlags("-std=c18", *flags)
                     arguments(
+                        "-DCMAKE_EXPORT_COMPILE_COMMANDS=ON",
                         "-DANDROID_STL=none",
                         "-DVERSION_CODE=$verCode",
                         "-DVERSION_NAME=$verName",