Hide symbols by default

Use cmake for better import/export defines
7 jobs for hide_symbols in 6 minutes and 29 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Build
passed #7444126
build

00:06:05

passed #7444131
build_android

00:00:38

passed #7444127
build_clang_libcpp

00:06:29

passed #7444130
build_clazy

00:05:28

passed #7444129
build_mingw64_fedora

00:02:34

passed #7444128
build_ubuntu_16_04

00:01:50

passed #7444125
clang_format

00:01:43