Makefile: fix make check so we can run in parallel.

And make travis use -j for `make check`

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

.travis/build.sh

@@ -45,7 +45,7 @@ if [ "$SOURCE_CHECK_ONLY" == "false" ]; then
     echo -en 'travis_fold:end:script.2\\r'
 
     echo -en 'travis_fold:start:script.3\\r'
-    make check
+    make -j$PYTEST_PAR check
     echo -en 'travis_fold:end:script.3\\r'
 else
     git clone https://github.com/lightningnetwork/lightning-rfc.git

Makefile

@@ -247,9 +247,7 @@ endif
 
 check-units:
 
-check: check-units
-	$(MAKE) installcheck
-	$(MAKE) pytest
+check: check-units installcheck pytest
 
 pytest: $(ALL_PROGRAMS)
 ifeq ($(PYTEST),)