Replace some external .h files in tests with inline C code in the test file that uses them.

tests/compile/cpp_enums.h

-enum Enum1 {
-  Item1,
-  Item2
-};
-
-namespace Namespace1 {
-  enum Enum2 {
-    Item3,
-    Item4
-  };
-}

tests/compile/cpp_enums.pyx

 # tag: cpp
 # mode: compile
 
-cdef extern from "cpp_enums.h":
+cdef extern from *:
+    """
+    enum Enum1 {
+        Item1,
+        Item2
+    };
+
+    """
     cdef enum Enum1:
         Item1
         Item2
@@ -13,7 +20,16 @@ cdef Enum1 x, y
 x = Item1
 y = Item2
 
-cdef extern from "cpp_enums.h" namespace "Namespace1":
+
+cdef extern from * namespace "Namespace1":
+    """
+    namespace Namespace1 {
+        enum Enum2 {
+            Item3,
+            Item4
+        };
+    }
+    """
     cdef enum Enum2:
         Item3
         Item4

tests/compile/crunchytype.h

-
-struct CrunchyType {
-  int number;
-  PyObject* string;
-};

tests/compile/crunchytype.pxd

-cdef extern from "crunchytype.h":
+cdef extern from *:
+    """
+    struct CrunchyType {
+        int number;
+        PyObject* string;
+    };
+    """
     cdef class crunchytype.Crunchy [ object CrunchyType ]:
         cdef int number
         cdef object string