NEX-2266 Shouldn't use mandoc binary from proto area during the build

@@ -76,8 +76,8 @@
 OBJS +=         compat_ohash.o
 
 CFLAGS +=       $(CC_VERBOSE)
 CSTD =  $(CSTD_GNU99)
 
-CPPFLAGS +=     -DOSNAME="\"illumos\""
+CPPFLAGS +=     -DOSNAME="\"NexentaStor\""
 
 LDLIBS +=       -lz