Make sure we make only one build type at the time.

Author: luca-heltai

.travis.yml

@@ -16,5 +16,5 @@ before_install:
 - ./scripts/dr.sh "./scripts/check_indentation.sh"
 
 script:
-- ./scripts/dr.sh "test -d build-travis && rm -rf build-travis; mkdir build-travis; cd build-travis; cmake -GNinja ../ -DBEM_ENABLE_TESTING=ON; ninja"
+- ./scripts/dr.sh "test -d build-travis && rm -rf build-travis; mkdir build-travis; cd build-travis; cmake -GNinja ../ -DBEM_ENABLE_TESTING=ON -DCMAKE_BUILD_TYPE=$BUILD_TYPE; ninja"
 - ./scripts/dr.sh "cd build-travis; ctest -N; ctest -V"