Allow C symbol file to be arch variant

The libclang_rt.* prebuilt libraries have an autogenerated map.txt for
each arch. e.g.
```
$ ls prebuilts/clang/host/linux-x86/clang-r530567/lib/clang/19/lib/linux/libclang_rt.asan*map.txt
prebuilts/clang/host/linux-x86/clang-r530567/lib/clang/19/lib/linux/libclang_rt.asan-aarch64-android.map.txt  prebuilts/clang/host/linux-x86/clang-r530567/lib/clang/19/lib/linux/libclang_rt.asan-riscv64-android.map.txt
prebuilts/clang/host/linux-x86/clang-r530567/lib/clang/19/lib/linux/libclang_rt.asan-arm-android.map.txt      prebuilts/clang/host/linux-x86/clang-r530567/lib/clang/19/lib/linux/libclang_rt.asan-x86_64-android.map.txt
prebuilts/clang/host/linux-x86/clang-r530567/lib/clang/19/lib/linux/libclang_rt.asan-i686-android.map.txt
```

These map.txt files are currently a noop, but will be used to compile
stub srcs. In preparation for that, make stubs.symbol_file and
llndk.symbol_file arch variant

Test: m nothing # no diff in ninja file
Bug: 220898484
Change-Id: I7316546905c1327c764ee67a48c77a2a68465d77
diff --git a/cc/library.go b/cc/library.go
index ff21cc3..092b177 100644
--- a/cc/library.go
+++ b/cc/library.go
@@ -64,7 +64,7 @@
 	Stubs struct {
 		// Relative path to the symbol map. The symbol map provides the list of
 		// symbols that are exported for stubs variant of this library.
-		Symbol_file *string `android:"path"`
+		Symbol_file *string `android:"path,arch_variant"`
 
 		// List versions to generate stubs libs for. The version name "current" is always
 		// implicitly added.
@@ -75,7 +75,7 @@
 		// implementation is made available by some other means, e.g. in a Microdroid
 		// virtual machine.
 		Implementation_installable *bool
-	}
+	} `android:"arch_variant"`
 
 	// set the name of the output
 	Stem *string `android:"arch_variant"`
@@ -118,7 +118,7 @@
 
 	// If this is an LLNDK library, properties to describe the LLNDK stubs.  Will be copied from
 	// the module pointed to by llndk_stubs if it is set.
-	Llndk llndkLibraryProperties
+	Llndk llndkLibraryProperties `android:"arch_variant"`
 
 	// If this is a vendor public library, properties to describe the vendor public library stubs.
 	Vendor_public_library vendorPublicLibraryProperties
diff --git a/cc/llndk_library.go b/cc/llndk_library.go
index 85c3edf..5ece78a 100644
--- a/cc/llndk_library.go
+++ b/cc/llndk_library.go
@@ -30,7 +30,7 @@
 type llndkLibraryProperties struct {
 	// Relative path to the symbol map.
 	// An example file can be seen here: TODO(danalbert): Make an example.
-	Symbol_file *string
+	Symbol_file *string `android:"path,arch_variant"`
 
 	// Whether to export any headers as -isystem instead of -I. Mainly for use by
 	// bionic/libc.