build: don't print installed files locally

It takes a significant amount of time to install neovim, and doubly so
on Windows, due to the sheer amount of files neovim ships with. On CI
this information may be important though, so we enable it if the
CI_ENABLE option is set to ON.

CMakeLists.txt

@@ -35,6 +35,10 @@ if(CCACHE_PRG)
   set(CMAKE_C_COMPILER_LAUNCHER ${CMAKE_COMMAND} -E env CCACHE_SLOPPINESS=pch_defines,time_macros ${CCACHE_PRG})
 endif()
 
+if(NOT CI_BUILD)
+  set(CMAKE_INSTALL_MESSAGE NEVER)
+endif()
+
 # Prefer our bundled versions of dependencies.
 if(DEFINED ENV{DEPS_BUILD_DIR})
   set(DEPS_PREFIX "$ENV{DEPS_BUILD_DIR}/usr" CACHE PATH "Path prefix for finding dependencies")