Fix parallel build 

http://bugs.gentoo.org/show_bug.cgi?id=311919

--- Makefile.in
+++ Makefile.in
@@ -82,9 +82,10 @@
 all: core 
 
 core:
-	(cd easel;     make CC="$(CC)" CFLAGS="$(CFLAGS)"; make)
-	(cd src;       make CC="$(CC)" CFLAGS="$(CFLAGS)"; make module)
-	(cd testsuite; make CC="$(CC)" CFLAGS="$(CFLAGS)")
+	$(MAKE) -C easel
+	$(MAKE) -C src 
+	$(MAKE) -C src module
+	$(MAKE) -C testsuite
 
 #.PHONY: $(RIGFILTERS)
 #$(RIGFILTERS): core
--- easel/Makefile.in
+++ easel/Makefile.in
@@ -132,7 +132,7 @@
 	esl_wuss.o
 
 all: libeasel.a
-	(cd miniapps; make)
+	$(MAKE) -C miniapps
 
 .c.o: 
 	${CC} -I. ${CFLAGS} ${SIMDFLAGS} ${DEFS} -c $<