tree b5544d584388d1bf2d229250f39a4e92e6e3d020
parent f2132c2a727c0b965bef99ac13441b5a3681c07d
author Michał Górny <mgorny@gentoo.org> 1575123236 +0100
committer Copybara-Service <copybara-worker@google.com> 1598638497 -0700

[libunwind] Emit dependent libraries only when detected by CMake

996e62eef75 added Linux-specific dependent libraries to libunwind
sources.  As a result, building libunwind with modern LLD on *BSD
started failing due to trying to link libdl.  Instead, add those
libraries only if they were detected by CMake.

While technically we could create a long list of systems that need -ldl
and -lpthread, maintaining a duplicate list makes little sense when
CMake needs to detect it for non-LLD systems anyway.  Remove existing
system exceptions since they should be covered by the CMake check
anyway.

Remove -D_LIBUNWIND_HAS_COMMENT_LIB_PRAGMA since it is no longer
explicitly needed, if we make the library-specific defines dependent
on presence of this pragma support.

Differential Revision: https://reviews.llvm.org/D70868

GitOrigin-RevId: 35bc5276ca31e3f0e8e87322153f410fa6224e59