skipping incompatible C:\GTEST\gtest-1.7.0\lib/libtest.a when searching for-ltest

I'm thinking of doing a unit test using Google test in Eclipse.

http://programingstudy2013.blogspot.jp/2014/08/eclipse-cdt-googletest.html
When I set it up and build it, I get the following error.

skipping incompatible C:\GTEST\gtest-1.7.0\lib/libtest.a when searching for-ltest

The environment is Windows 7 64bit.Eclipse uses Mars from Pleiades All in One.I use the MinGW that came with Eclipse as it is.

Please tell me the cause and how to deal with it.