Add the default definition of configPRECONDITION to FreeRTOS.h.

This is needed for CBMC proofs.

FreeRTOS/Source/include/FreeRTOS.h

@@ -241,6 +241,19 @@ extern "C" {
 	#define configASSERT_DEFINED 1
 #endif
 
+/* configPRECONDITION should resolve to configASSERT. The CBMC proofs need a way
+to track assumptions and assertions.
+- A configPRECONDITION statement should express an implicit invariant or
+assumption made.
+- A configASSERT statement should express an invariant that must hold explicit
+before calling the code. */
+#ifndef configPRECONDITION
+	#define configPRECONDITION( X ) configASSERT(X)
+	#define configPRECONDITION_DEFINED 0
+#else
+	#define configPRECONDITION_DEFINED 1
+#endif
+
 #ifndef portMEMORY_BARRIER
 	#define portMEMORY_BARRIER()
 #endif