bpo-395222: Correctly unparse unicode prefix in ast_unparse.c (GH-19512)

diff --git a/Lib/test/test_future.py b/Lib/test/test_future.py
index ebeb833..0522003 100644
--- a/Lib/test/test_future.py
+++ b/Lib/test/test_future.py
@@ -153,6 +153,7 @@
         eq = self.assertAnnotationEqual
         eq('...')
         eq("'some_string'")
+        eq("u'some_string'")
         eq("b'\\xa3'")
         eq('Name')
         eq('None')
diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-04-14-18-47-00.bpo-39522.uVeIV_.rst b/Misc/NEWS.d/next/Core and Builtins/2020-04-14-18-47-00.bpo-39522.uVeIV_.rst
new file mode 100644
index 0000000..12d939d
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2020-04-14-18-47-00.bpo-39522.uVeIV_.rst
@@ -0,0 +1,2 @@
+Correctly unparse explicit ``u`` prefix for strings when postponed
+evaluation for annotations activated. Patch by Batuhan Taskaya.
diff --git a/Python/ast_unparse.c b/Python/ast_unparse.c
index 7cf199b..c321acf 100644
--- a/Python/ast_unparse.c
+++ b/Python/ast_unparse.c
@@ -875,6 +875,8 @@
         if (e->v.Constant.value == Py_Ellipsis) {
             APPEND_STR_FINISH("...");
         }
+        APPEND_STR_IF(e->v.Constant.kind != NULL,
+                      PyUnicode_AS_DATA(e->v.Constant.kind));
         return append_ast_constant(writer, e->v.Constant.value);
     case JoinedStr_kind:
         return append_joinedstr(writer, e, false);