Reduce parallelism on Travis because it runs out of memory.

.travis.yml

@@ -14,4 +14,4 @@ addons:
 before_install:
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew update; fi
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew install automake autoconf libtool; fi
-script: ./super-test.sh quick
+script: ./super-test.sh -j2 quick  # limit parallelism due to limited memory on Travis

super-test.sh

@@ -13,6 +13,9 @@ PARALLEL=$(nproc 2>/dev/null || echo 1)
 
 while [ $# -gt 0 ]; do
   case "$1" in
+    -j* )
+      PARALLEL=${1#-j}
+      ;;
     test )
       ;;  # nothing
     quick )