Remove obsolete policy settings

Summary:
The line

 cmake_minimum_required(VERSION 3.4.3)

already has the effect of setting to NEW all policies present in that
release:

 https://cmake.org/cmake/help/v3.4/manual/cmake-policies.7.html

Subscribers: mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D50407

llvm-svn: 339376

llvm/CMakeLists.txt

@@ -2,21 +2,13 @@
 
 cmake_minimum_required(VERSION 3.4.3)
 
-cmake_policy(SET CMP0022 NEW)
-
-cmake_policy(SET CMP0048 NEW)
-
 # CMake 3.1 and higher include generator expressions of the form
 # $<TARGETLIB:obj> in the SOURCES property.  These need to be
 # stripped everywhere that access the SOURCES property, so we just
 # defer to the OLD behavior of not including generator expressions
 # in the output for now.
 cmake_policy(SET CMP0051 OLD)
 
-cmake_policy(SET CMP0056 NEW)
-
-cmake_policy(SET CMP0057 NEW)
-
 if(POLICY CMP0068)
   cmake_policy(SET CMP0068 NEW)
   set(CMAKE_BUILD_WITH_INSTALL_NAME_DIR ON)