misc/protoshoot: option to disable sctp with SCTP=0 in make command

misc/tools/protoshoot/Makefile

@@ -1,6 +1,6 @@
 #
 
-COREPATH=../../src
+COREPATH=../../../src
 include $(COREPATH)/Makefile.defs
 include $(COREPATH)/Makefile.targets
 
@@ -8,8 +8,12 @@ auto_gen=
 NAME=protoshoot
 RELEASE=0.2
 
+ifeq ($(SCTP),0)
+C_DEFS:=$(filter-out -DUSE_SCTP, $(C_DEFS))
+else
 ifneq (,$(findstring -DUSE_SCTP,$(C_DEFS)))
-SCTP=1
+SCTP?=1
+endif
 endif
 
 ifeq ($(SCTP),1)