Move Travis CI build steps to separate script that can build/run tests with C++11 enabled (when compiled with clang)

.travis.yml

@@ -12,12 +12,5 @@ before_install:
 install:
   - sudo apt-get install -y --force-yes libboost1.55-dev libboost-regex1.55-dev
 
-before_script:
-  - mkdir -p build
-
 script:
-  - pushd build
-  - cmake ..
-  - make
-  - ./test_suite
-  - popd
+  - ./travis.sh

travis.sh

@@ -0,0 +1,40 @@
+#!/bin/bash
+
+set -e   # (errexit) Exit if any subcommand or pipeline returns a non-zero status
+set -u   # (nounset) Exit on any attempt to use an uninitialised variable
+
+: ${CXX:=}
+: ${TRAVIS:=false}
+
+echo -n "Checking that we're running on Travis CI..."
+if [[ $TRAVIS == 'true' ]]; then
+	echo " OK"
+else
+	echo " Nope."
+	echo "This script is only intended for use on Travis CI."
+	echo "Set the TRAVIS environment variable to 'true' to override."
+	exit 1
+fi
+
+mkdir -p build
+pushd build
+
+echo "Attempting to build and run test suite with C++11 support disabled..."
+cmake -DVALIJSON_CXX11_ADAPTERS=disabled ..
+make
+./test_suite
+
+echo "Checking if current compiler is GCC..."
+if [[ $CXX == 'g++' ]]; then
+	echo "Not building test suite with C++11 support due to ancient version of GCC on Travis CI"
+else
+	echo "Attempting to build and run test suite with C++11 support enabled..."
+	make clean
+	cmake -DVALIJSON_CXX11_ADAPTERS=enabled ..
+	make
+	./test_suite
+fi
+
+make clean
+
+popd