cmake HAVE_GNUTLS examples

TigerVNC/tigervnc CMakeLists.txt :327 

add_definitions("-DHAVE_GNUTLS")

nih-at/libzip lib/CMakeLists.txt :162 

elseif(HAVE_GNUTLS)

flyinghead/flycast core/deps/libzip/lib/CMakeLists.txt :159 

elseif(HAVE_GNUTLS)