also test building with gyp on travis

.travis.yml

@@ -17,4 +17,5 @@ before_script:
  - if [ "${CXX}" = 'g++' ]; then export CXX="g++-4.7"; export CC="gcc-4.7"; make test bench; make clean; export CXX="g++-4.8"; export CC="gcc-4.8"; make test bench; else make test bench; fi;
 
 script:
- - make sizes /usr/include/boost/variant.hpp
+ - make sizes /usr/include/boost/variant.hpp
+ - make gyp

Makefile

@@ -25,6 +25,14 @@ endif
 
 all: out/bench-variant out/unique_ptr_test out/unique_ptr_test out/recursive_wrapper_test out/binary_visitor_test
 
+./deps/gyp:
+	git clone --depth 1 https://chromium.googlesource.com/external/gyp.git ./deps/gyp
+
+gyp: ./deps/gyp
+	deps/gyp/gyp --depth=. -Goutput_dir=./ --generator-output=./out -f make
+	make V=1 -C ./out tests
+	./out/Release/tests
+
 out/bench-variant-debug: Makefile test/bench_variant.cpp variant.hpp
 	mkdir -p ./out
 	$(CXX) -o out/bench-variant-debug test/bench_variant.cpp -I./ $(DEBUG_FLAGS) $(COMMON_FLAGS) $(CXXFLAGS) $(LDFLAGS) $(BOOST_LIBS)