[clang] [libclang] Add clang_CXXMethod_getQualifiers, clang_Cursor_isConstexpr, and clang_CXXMethod_isExplicitObjectMemberFunction (PR #183305)

[Aaron Ballman via cfe-commits]

================
@@ -9533,6 +9533,33 @@ unsigned clang_CXXMethod_isConst(CXCursor C) {
   return (Method && Method->getMethodQualifiers().hasConst()) ? 1 : 0;
 }
 
+CXQualifiers clang_CXXMethod_getQualifiers(CXCursor C) {
+  CXQualifiers Q = {};
+  if (!clang_isDeclaration(C.kind))
+    return Q;
+
+  const Decl *D = cxcursor::getCursorDecl(C);
+  const CXXMethodDecl *Method =
+      D ? dyn_cast_or_null<CXXMethodDecl>(D->getAsFunction()) : nullptr;
+  if (Method) {
+    Qualifiers MQ = Method->getMethodQualifiers();
+    Q.Const = MQ.hasConst();
+    Q.Volatile = MQ.hasVolatile();
+    Q.Restrict = MQ.hasRestrict();
+  }
+  return Q;
+}
+
+unsigned clang_CXXMethod_isExplicitObjectMemberFunction(CXCursor C) {
+  if (!clang_isDeclaration(C.kind))
+    return 0;
+
+  const Decl *D = cxcursor::getCursorDecl(C);
+  const CXXMethodDecl *Method =
+      D ? dyn_cast_or_null<CXXMethodDecl>(D->getAsFunction()) : nullptr;
+  return (Method && Method->isExplicitObjectMemberFunction()) ? 1 : 0;
----------------
AaronBallman wrote:

```suggestion
  return Method && Method->isExplicitObjectMemberFunction();
```
No need to do the conversion explicitly, the implicit conversion will get the same values. I don't insist either, it's not wrong as-is.

https://github.com/llvm/llvm-project/pull/183305