Index: generic/nsf.h
===================================================================
diff -u -re6ceb1ea38f6aada0281a8e7d5e5fed37578eca6 -r5783e727c52c408aeecaca7f2870ea732ee3fc2d
--- generic/nsf.h	(.../nsf.h)	(revision e6ceb1ea38f6aada0281a8e7d5e5fed37578eca6)
+++ generic/nsf.h	(.../nsf.h)	(revision 5783e727c52c408aeecaca7f2870ea732ee3fc2d)
@@ -146,6 +146,22 @@
 #define PER_OBJECT_PARAMETER_CACHING 1
 
 /*
+  The NsfConfigEnabled() macro allows for querying whether a
+  configuration macro (see above) is actually defined (and
+  whether it expands to 1). This macro can used in CPP expressions
+  preprocessing time (e.g., "#if NsfConfigEnabled(...)") as well as in
+  C expressions (e.g., "if(NsfConfigEnabled(...))")
+
+  Adapted from https://plus.google.com/+LinusTorvalds/posts/9gntjh57dXt
+*/
+
+#define NsfConfigEnabled(macro) NsfConfigEnabled_(macro)
+#define NsfMacroTest_1 ,
+#define NsfConfigEnabled_(value) NsfConfigEnabled__(NsfMacroTest_##value)
+#define NsfConfigEnabled__(comma) NsfConfigEnabled___(comma 1, 0)
+#define NsfConfigEnabled___(_, v, ...) v
+
+/*
  * Sanity checks and dependencies for optional compile flags
  */
 #if defined(PARSE_TRACE_FULL)