Travis single process build to avoid OOM

Author: alanz

.travis.yml

@@ -27,13 +27,15 @@ install:
   # Bring in GHC if not already present
   - ./travis_long stack +RTS -N2 -RTS setup
   # Build the dependencies only.
-  - ./travis_long stack +RTS -N2 -RTS build --only-snapshot --pedantic
+  # - ./travis_long stack +RTS -N2 -RTS build --only-snapshot --pedantic
+  - ./travis_long stack build --only-snapshot --pedantic
 
 script:
-  # - ./travis_long stack +RTS -N2 -RTS build --pedantic
-  - ./travis_long stack +RTS -N2 -RTS build
+  - ./travis_long stack build --pedantic
+  # - ./travis_long stack +RTS -N2 -RTS build
   # - ./travis_long stack +RTS -N2 -RTS build --test --pedantic
-  - ./travis_long stack +RTS -N2 -RTS build --test
+  - ./travis_long stack build --test --pedantic
+  # - ./travis_long stack +RTS -N2 -RTS build --test
   - ./travis_long stack exec emacs24 -- -q --batch -L elisp -l elisp/tests/haskell-ide-engine-tests.el -f ert-run-tests-batch-and-exit
   # Re-enable the haddock tests when the warning in HaRe does not trigger a problem
   # - ./travis_long stack +RTS -N2 -RTS build --test --haddock