make build fail on errors; restore use_threadpool

Makefile

@@ -23,11 +23,11 @@ clean:
 
 .PHONY: modules
 modules:
-	-@for r in $(subdirs) "" ; do \
+	@for r in $(subdirs) "" ; do \
 		if [ -n "$$r" ]; then \
 			echo  "" ; \
 			echo  "making $$r" ; \
-			$(MAKE) -C $$r all; \
+			$(MAKE) -C $$r all || exit 1; \
 		fi ; \
 	done 
 

Makefile.defs

@@ -21,7 +21,7 @@ endif
 #version number
 VERSION = 1
 PATCHLEVEL = 4
-SUBLEVEL = 3
+SUBLEVEL = 3 
 
 ifneq ($(SCM_REV),)
 RELEASE = $(SCM_REV)
@@ -50,7 +50,7 @@ CPPFLAGS += -D_DEBUG \
 #      if compiled without thread pool support, every
 #      session will have its own thread.
 #
-#USE_THREADPOOL = yes
+USE_THREADPOOL = yes
 
 # compile with spandsp DTMF detection? see soft-switch.org
 #   this needs a fairly new version of spandsp - tested with 0.0.4pre11