[MERGE #1219 @digitalinfinity] Return exit code from linux build script

Merge pull request #1219 from digitalinfinity:fail_lb

build.sh

@@ -151,4 +151,10 @@ echo Generating $BUILD_TYPE makefiles
 cmake $CMAKE_GEN $CC_PREFIX $ICU_PATH -DCMAKE_BUILD_TYPE=$BUILD_TYPE ..
 
 $MAKE $MULTICORE_BUILD 2>&1 | tee build.log
+_RET=${PIPESTATUS[0]}
+if [[ $_RET != 0 ]]; then
+    echo Error: $MAKE return $_RET
+fi
+
 popd > /dev/null
+exit $_RET