Windows: Enable issue 70093 link tests

Author: ChrisDenton

src/tools/tidy/src/issues.txt

@@ -2710,8 +2710,6 @@ ui/limits/issue-75158-64.rs
 ui/link-native-libs/issue-109144.rs
 ui/link-native-libs/issue-43925.rs
 ui/link-native-libs/issue-43926.rs
-ui/link-native-libs/issue-70093/issue-70093-link-directives.rs
-ui/link-native-libs/issue-70093/issue-70093.rs
 ui/linkage-attr/auxiliary/issue-12133-dylib.rs
 ui/linkage-attr/auxiliary/issue-12133-dylib2.rs
 ui/linkage-attr/auxiliary/issue-12133-rlib.rs

tests/ui/link-native-libs/issue-70093/issue-70093-link-directives.rs renamed to tests/ui/link-native-libs/issue-70093/link-directives.rs

@@ -1,6 +1,5 @@
 //@ run-pass
 //@ compile-flags: -Zlink-directives=no
-//@ ignore-windows - this will probably only work on unixish systems
 //@ ignore-fuchsia - missing __libc_start_main for some reason (#84733)
 //@ ignore-cross-compile - default-linker-libraries=yes doesn't play well with cross compiling
 

tests/ui/link-native-libs/issue-70093/link-native-libraries-msvc.rs

@@ -0,0 +1,14 @@
+// On Windows MSVC, default-linker-libraries=yes doesn't work because
+// rustc drives the linker directly instead of going through another compiler.
+// Therefore rustc would need to implement default-linker-libraries itself but doesn't.
+// So instead we use -Clink-arg to directly set the required msvcrt.lib as a link arg.
+
+//@ run-pass
+//@ compile-flags: -Zlink-native-libraries=no -Clink-arg=msvcrt.lib
+//@ only-msvc
+//@ ignore-cross-compile
+
+#[link(name = "some-random-non-existent-library", kind = "static")]
+extern "C" {}
+
+fn main() {}