Fix -Wdeprecated-declarations warning from clang

[sendaoYan]

Hi all,

This PR disable the -Wdeprecated-declarations compiler warning for clang explicitly. The issue detail shows in #4935

Why not add "-Wno-deprecated-declarations" to makefile to disable the compiler waning? Because OpenJDK will include the whole gtest source and build the gtest with their makefile, disable the compiler warning in source will avoid these project do this disable work again.

[google-cla]

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[sendaoYan]

Sorry I used the wrong email address, and cause the cla check report fails. So I edit the email address in the commit log and had to push forced.