Rust: add test with extern block

Author: aibaars

rust/ql/test/extractor-tests/canonical_path/canonical_paths.expected

@@ -25,6 +25,7 @@ canonicalPath
 | regular.rs:40:1:46:1 | fn enum_qualified_usage | test::regular::enum_qualified_usage |
 | regular.rs:48:1:55:1 | fn enum_unqualified_usage | test::regular::enum_unqualified_usage |
 | regular.rs:57:1:63:1 | fn enum_match | test::regular::enum_match |
+| regular.rs:69:1:71:1 | fn is_number_or_letter | test::regular::is_number_or_letter |
 canonicalPaths
 | anonymous.rs:1:1:1:26 | use ...::Trait | None | None |
 | anonymous.rs:3:1:32:1 | fn canonicals | repo::test | crate::anonymous::canonicals |
@@ -65,6 +66,9 @@ canonicalPaths
 | regular.rs:48:1:55:1 | fn enum_unqualified_usage | repo::test | crate::regular::enum_unqualified_usage |
 | regular.rs:51:5:51:18 | use MyEnum::* | None | None |
 | regular.rs:57:1:63:1 | fn enum_match | repo::test | crate::regular::enum_match |
+| regular.rs:65:1:67:1 | ExternBlock | None | None |
+| regular.rs:66:5:66:40 | fn is_alphanum | repo::test | ::is_alphanum |
+| regular.rs:69:1:71:1 | fn is_number_or_letter | repo::test | crate::regular::is_number_or_letter |
 resolvedPaths
 | anonymous.rs:27:17:27:30 | OtherStruct {...} | None | None |
 | anonymous.rs:28:9:28:9 | s | None | None |
@@ -96,3 +100,5 @@ resolvedPaths
 | regular.rs:59:9:59:24 | ...::Variant1 | repo::test | crate::regular::MyEnum::Variant1 |
 | regular.rs:60:9:60:27 | ...::Variant2(...) | repo::test | crate::regular::MyEnum::Variant2 |
 | regular.rs:61:9:61:31 | ...::Variant3 {...} | repo::test | crate::regular::MyEnum::Variant3 |
+| regular.rs:70:14:70:24 | is_alphanum | repo::test | ::is_alphanum |
+| regular.rs:70:26:70:28 | chr | None | None |

rust/ql/test/extractor-tests/canonical_path/regular.rs

@@ -61,3 +61,11 @@ fn enum_match(e: MyEnum) {
         MyEnum::Variant3 { .. } => {}
     }
 }
+
+extern "C" {
+    pub fn is_alphanum(chr: u8) -> bool;
+}
+
+pub fn is_number_or_letter(chr: u8) -> bool {
+    unsafe { is_alphanum(chr) }
+}