rust: Link with rlib external dependencies

When linking with a Rust rlib, we should also link with its external
system dependencies. This was currently done only for C ABI crates, do
it for both rlib and staticlib now.

mesonbuild/backend/ninjabackend.py

@@ -1979,6 +1979,8 @@ def _link_library(libname: str, static: bool, bundle: bool = False):
         for d in target_deps:
             linkdirs.add(d.subdir)
             deps.append(self.get_dependency_filename(d))
+            if isinstance(d, build.StaticLibrary):
+                external_deps.extend(d.external_deps)
             if d.uses_rust_abi():
                 if d not in itertools.chain(target.link_targets, target.link_whole_targets):
                     # Indirect Rust ABI dependency, we only need its path in linkdirs.
@@ -1993,9 +1995,6 @@ def _link_library(libname: str, static: bool, bundle: bool = False):
 
             # Link a C ABI library
 
-            if isinstance(d, build.StaticLibrary):
-                external_deps.extend(d.external_deps)
-
             # Pass native libraries directly to the linker with "-C link-arg"
             # because rustc's "-l:+verbatim=" is not portable and we cannot rely
             # on linker to find the right library without using verbatim filename.

test cases/rust/24 system deps/main.rs

@@ -0,0 +1,5 @@
+extern crate wrapper;
+
+fn main() {
+    wrapper::func();
+}

test cases/rust/24 system deps/meson.build

@@ -0,0 +1,9 @@
+project('system deps', 'rust')
+
+glib = dependency('glib-2.0', required: false)
+if not glib.found()
+  error('MESON_SKIP_TEST: Need glib system dependency')
+endif
+
+rlib = static_library('wrapper', 'wrapper.rs', dependencies: glib)
+exe = executable('main', 'main.rs', link_with: rlib)

test cases/rust/24 system deps/wrapper.rs

@@ -0,0 +1,9 @@
+extern "C" {
+    fn g_hash_table_new() -> *mut std::ffi::c_void;
+}
+
+pub fn func() {
+    unsafe {
+        g_hash_table_new();
+    }
+}