Move conditional configuration related UI tests into their own directory

src/test/ui/conditional-compilation/cfg-attr-syntax-validation.rs

@@ -0,0 +1,32 @@
+#[cfg] //~ ERROR `cfg` is not followed by parentheses
+struct S1;
+
+#[cfg = 10] //~ ERROR `cfg` is not followed by parentheses
+struct S2;
+
+#[cfg()] //~ ERROR `cfg` predicate is not specified
+struct S3;
+
+#[cfg(a, b)] //~ ERROR multiple `cfg` predicates are specified
+struct S4;
+
+#[cfg("str")] //~ ERROR `cfg` predicate key cannot be a literal
+struct S5;
+
+#[cfg(a::b)] //~ ERROR `cfg` predicate key must be an identifier
+struct S6;
+
+#[cfg(a())] //~ ERROR invalid predicate `a`
+struct S7;
+
+#[cfg(a = 10)] //~ ERROR literal in `cfg` predicate value must be a string
+struct S8;
+
+macro_rules! generate_s9 {
+    ($expr: expr) => {
+        #[cfg(feature = $expr)] //~ ERROR `cfg` is not a well-formed meta-item
+        struct S9;
+    }
+}
+
+generate_s9!(concat!("nonexistent"));