CMake: control static/shared the normal CMake way.

This flips the default build mode to create a static libskia.

To create a shared libskia, pass -DBUILD_SHARED_LIBS=1 when running cmake.

BUG=skia:5341
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2009503002
CQ_EXTRA_TRYBOTS=client.skia.compile:Build-Ubuntu-GCC-x86_64-Release-CMake-Trybot,Build-Mac-Clang-x86_64-Release-CMake-Trybot

Review-Url: https://codereview.chromium.org/2009503002
2 files changed