fix structmember.h defines in cython 3

Author: infmagic2047

src/sage/libs/gap/gap_includes.pxd

@@ -144,3 +144,18 @@ cdef extern from "gap/stringobj.h" nogil:
     bint IS_STRING(Obj obj)
     bint IsStringConv(Obj obj)
     Obj NEW_STRING(Int)
+
+
+cdef extern from "<structmember.h>" nogil:
+    """
+    /* Hack: Cython 3.0 automatically includes <structmember.h>, which
+     * defines several macros that collides with enum definitions in
+     * gap/objects.h. We need to include the header explicitly and
+     * undefine these macros.
+     */
+    #undef T_INT
+    #undef T_STRING
+    #undef T_CHAR
+    #undef T_BOOL
+    """
+    pass