OS-1723 DTrace should speak JSON (review fixes)

@@ -50,10 +50,11 @@
 DTRACE_INC_32   = -I$(UTSBASE)/sparc/v7
 DTRACE_INC_64   = -I$(UTSBASE)/sparc/v9
 
 CFLAGS += $(CCVERBOSE)
 CPPFLAGS += $(DTRACE_INC_$(CLASS))
+CPPFLAGS += -I$(SRC)/common/util
 
 DTRACE_XAS_32   = -xarch=v8plus
 DTRACE_XAS_64   = -xarch=v9
 
 AS_CPPFLAGS     += $(DTRACE_INC_64)