[SR-8889] CMake warning for cmark about policy CMP0063

[kevints]

Previous ID	SR-8889
Radar	None
Original Reporter	@kevints
Type	Bug

Environment

Ubuntu 14.04
Swift 4.2-RELEASE
cmake 3.5.2

Additional Detail from JIRA

Votes	0
Component/s	Source Tooling
Labels	Bug, CMake
Assignee	None
Priority	Medium

md5: e8984f5e3ecc0f59365859c9fe4e1317

Issue Description:

This warning always appears in the build output for cmark.

CMake Warning (dev) at src/CMakeLists.txt:84 (add_library):
  Policy CMP0063 is not set: Honor visibility properties for all target
  types.  Run "cmake --help-policy CMP0063" for policy details.  Use the
  cmake_policy command to set the policy and suppress this warning.

  Target "libcmark_static" of type "STATIC_LIBRARY" has the following
  visibility properties set for C:

    C_VISIBILITY_PRESET

  For compatibility CMake is not honoring them for this target.
This warning is for project developers.  Use -Wno-dev to suppress it.

[belkadan]

@tkremenek, @akyrtzi, Rostepher (JIRA User), something else to check when we update to a newer CMark?

[akyrtzi]

I don't see why we need to wait until we update to newer CMark, can't we make the (probably simple) CMake change to make the warning go away ?

[belkadan]

Sure, we could also do that. If upstream already has a fix it'd be nice to fix it the same way, is all.

[akyrtzi]

Rostepher (JIRA User) are you fine with creating a PR to suppress this warning ?