Enable debug info in Rust modules.

This allows tombstones to be symbolized and is consistent with C/C++
where we pass -g.

Bug: 173723155
Change-Id: I597e2bf97517407b428277f1cf7aa19b73371efa
diff --git a/rust/config/global.go b/rust/config/global.go
index 22d9567..b7fff4a 100644
--- a/rust/config/global.go
+++ b/rust/config/global.go
@@ -44,6 +44,7 @@
 	GlobalRustFlags = []string{
 		"--remap-path-prefix $$(pwd)=",
 		"-C codegen-units=1",
+		"-C debuginfo=2",
 		"-C opt-level=3",
 		"-C relocation-model=pic",
 	}