vmbase/pvmfw: Extract common build properties to defaults

All vmbase-based projects follow the same structure of build targets.
Extract common properties of their build rules into defaults.

vmbase_rust_defaults: rust_* targets, no-std, arm64 only
vmbase_cc_defaults: cc_* targets, no std, arm64 only
vmbase_elf_defaults: cc_binary, arm64 only, link vmbase_entry

Test: m pvmfw vmbase_example
Change-Id: I635ce939fd349b9ce02d20c26e48a95e8b84ca50
diff --git a/vmbase/example/Android.bp b/vmbase/example/Android.bp
index 4011807..e11bb2f 100644
--- a/vmbase/example/Android.bp
+++ b/vmbase/example/Android.bp
@@ -4,57 +4,33 @@
 
 rust_ffi_static {
     name: "libvmbase_example",
+    defaults: ["vmbase_ffi_defaults"],
     crate_name: "vmbase_example",
     srcs: ["src/main.rs"],
     edition: "2021",
-    no_stdlibs: true,
-    stdlibs: [
-        "libcompiler_builtins.rust_sysroot",
-        "libcore.rust_sysroot",
-    ],
     rustlibs: [
         "libaarch64_paging",
         "libbuddy_system_allocator",
         "liblog_rust_nostd",
         "libvmbase",
     ],
-    enabled: false,
-    target: {
-        android_arm64: {
-            enabled: true,
-        },
-    },
     apex_available: ["com.android.virt"],
 }
 
 cc_binary {
     name: "vmbase_example_elf",
     stem: "vmbase_example",
+    defaults: ["vmbase_elf_defaults"],
     srcs: [
         "idmap.S",
     ],
     static_libs: [
-        "libvmbase_entry",
         "libvmbase_example",
     ],
-    static_executable: true,
-    nocrt: true,
-    system_shared_libs: ["libc"],
-    stl: "none",
     linker_scripts: [
         "image.ld",
         ":vmbase_sections",
     ],
-    installable: false,
-    enabled: false,
-    target: {
-        android_arm64: {
-            enabled: true,
-        },
-    },
-    sanitize: {
-        hwaddress: false,
-    },
     apex_available: ["com.android.virt"],
 }