compiler: Restore macros ordering after rebase

Author: georgebisbas

devito/passes/iet/misc.py

@@ -151,8 +151,10 @@ def _generate_macros(iet, tracker=None, **kwargs):
     headers = sorted((ccode(define), ccode(expr)) for define, expr in headers)
 
     # Generate Macros from higher-level SymPy objects
-    applications = FindApplications().visit(iet)
-    headers = set().union(*[_generate_macros(i) for i in applications])
+    headers.extend(_generate_macros_math(iet))
+
+    # Remove redundancies while preserving the order
+    headers = filter_ordered(headers)
 
     # Some special Symbols may represent Macros defined in standard libraries,
     # so we need to include the respective includes