Support multiple crtbegin and crtend dependencies

Musl libc with an embedded linker uses multiple crtbegin dependencies,
convert rust's CrtBegin and CrtEnd to lists.

Bug: 190084016
Test: m USE_HOST_MUSL=true host-native
Change-Id: Ie843801e87b1f38ace84502d9e4f938a92ec1fa2
diff --git a/rust/library.go b/rust/library.go
index bb2e83f..9d79c53 100644
--- a/rust/library.go
+++ b/rust/library.go
@@ -428,8 +428,8 @@
 
 	if ctx.toolchain().Bionic() && (library.dylib() || library.shared()) {
 		deps = bionicDeps(ctx, deps, false)
-		deps.CrtBegin = "crtbegin_so"
-		deps.CrtEnd = "crtend_so"
+		deps.CrtBegin = []string{"crtbegin_so"}
+		deps.CrtEnd = []string{"crtend_so"}
 	}
 
 	return deps