Add lua.cross to CI tests. (#1649)

.travis.yml

@@ -5,13 +5,21 @@ addons:
     packages:
     - python-serial
     - srecord
+    - lua5.1
 cache:
-  directories:
+  - pip
+  - directories:
     - cache
+before_install:
+- pip install --user hererocks
+- hererocks env --lua 5.1 -rlatest
+- source env/bin/activate
+- luarocks install luafilesystem
 install:
 - tar -zxvf tools/esp-open-sdk.tar.gz
 - export PATH=$PATH:$PWD/esp-open-sdk/xtensa-lx106-elf/bin
 script:
+- lua tools/cross-lua.lua || exit 1
 - export BUILD_DATE=$(date +%Y%m%d)
 - make EXTRA_CCFLAGS="-DBUILD_DATE='\"'$BUILD_DATE'\"'" all
 - cd bin/