Turn on EXPORT_COMPILE_COMMANDS

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

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

.gitignore

@@ -1,5 +1,6 @@
 .project
 .settings
+.cache
 *.iml
 .gradle
 /local.properties

build.gradle.kts

@@ -35,7 +35,8 @@ cmaker {
             arrayOf(
                 "-DEXTERNAL_ROOT=${File(rootDir.absolutePath, "external")}",
                 "-DCORE_ROOT=${File(rootDir.absolutePath, "core/src/main/jni")}",
-                "-DANDROID_STL=none"
+                "-DANDROID_STL=none",
+                "-DCMAKE_EXPORT_COMPILE_COMMANDS=ON",
             )
         )
         val flags = arrayOf(
@@ -88,6 +89,7 @@ subprojects {
             externalNativeBuild {
                 cmake {
                     version = "3.28.1+"
+                    buildStagingDirectory = layout.buildDirectory.get().asFile
                 }
             }