[CMake] Fully delete the deprecated LLVM_USE_CRT* (llvm#66850)

This has been deprecated in favor of CMake's CMAKE_MSVC_RUNTIME_LIBRARY
in c6bd873 .
Current release branch still contains it in deprecated status so no
existing end-users will be affected.

Author: Naville

clang/cmake/caches/CrossWinToARMLinux.cmake

@@ -95,7 +95,6 @@ set(CLANG_DEFAULT_LINKER                    "lld" CACHE STRING "")
 
 if(WIN32)
   set(CMAKE_MSVC_RUNTIME_LIBRARY            "MultiThreaded" CACHE STRING "")
-  set(LLVM_USE_CRT_RELEASE                  "MT" CACHE STRING "")
 endif()
 
 # Set up RPATH for the target runtime/builtin libraries.

clang/cmake/caches/Fuchsia-stage2.cmake

@@ -30,7 +30,6 @@ set(LLDB_ENABLE_CURSES OFF CACHE BOOL "")
 set(LLDB_ENABLE_LIBEDIT OFF CACHE BOOL "")
 
 if(WIN32)
-  set(LLVM_USE_CRT_RELEASE "MT" CACHE STRING "")
   set(FUCHSIA_DISABLE_DRIVER_BUILD ON)
 endif()
 

clang/cmake/caches/Fuchsia.cmake

@@ -70,10 +70,6 @@ foreach(variable ${_FUCHSIA_BOOTSTRAP_PASSTHROUGH})
   endif()
 endforeach()
 
-if(WIN32)
-  set(LLVM_USE_CRT_RELEASE "MT" CACHE STRING "")
-endif()
-
 set(CLANG_DEFAULT_CXX_STDLIB libc++ CACHE STRING "")
 set(CLANG_DEFAULT_LINKER lld CACHE STRING "")
 set(CLANG_DEFAULT_OBJCOPY llvm-objcopy CACHE STRING "")

llvm/cmake/modules/ChooseMSVCCRT.cmake

@@ -470,7 +470,6 @@ endif()
 option(LLVM_ENABLE_WARNINGS "Enable compiler warnings." ON)
 
 if( MSVC )
-  include(ChooseMSVCCRT)
 
   # Add definitions that make MSVC much less annoying.
   add_compile_definitions(
@@ -951,7 +950,7 @@ if(LLVM_USE_SANITIZER)
       endif()
       # Prepare ASAN runtime if needed
       if (LLVM_USE_SANITIZER MATCHES ".*Address.*")
-        if (${LLVM_USE_CRT_${uppercase_CMAKE_BUILD_TYPE}} MATCHES "^(MT|MTd)$")
+        if (${CMAKE_MSVC_RUNTIME_LIBRARY} MATCHES "^(MultiThreaded|MultiThreadedDebug)$")
           append("/wholearchive:clang_rt.asan-${arch}.lib /wholearchive:clang_rt.asan_cxx-${arch}.lib"
             CMAKE_EXE_LINKER_FLAGS)
           append("/wholearchive:clang_rt.asan_dll_thunk-${arch}.lib"

llvm/cmake/modules/HandleLLVMOptions.cmake

@@ -14,10 +14,7 @@ set(LLVM_PACKAGE_BUGREPORT @PACKAGE_BUGREPORT@)
 
 set(LLVM_BUILD_TYPE @CMAKE_BUILD_TYPE@)
 
-set(LLVM_USE_CRT_DEBUG @LLVM_USE_CRT_DEBUG@)
-set(LLVM_USE_CRT_MINSIZEREL @LLVM_USE_CRT_MINSIZEREL@)
-set(LLVM_USE_CRT_RELEASE @LLVM_USE_CRT_RELEASE@)
-set(LLVM_USE_CRT_RELWITHDEBINFO @LLVM_USE_CRT_RELWITHDEBINFO@)
+set(CMAKE_MSVC_RUNTIME_LIBRARY @CMAKE_MSVC_RUNTIME_LIBRARY@)
 
 set(LLVM_USE_SPLIT_DWARF @LLVM_USE_SPLIT_DWARF@)
 

llvm/cmake/modules/LLVMConfig.cmake.in

@@ -777,12 +777,6 @@ enabled sub-projects. Nearly all of these variable names begin with
   ``LLVM_USE_SANITIZER`` contains ``Undefined``. This can be used to override
   the default set of UBSan flags.
 
-**LLVM_USE_CRT_{target}**:STRING
-  On Windows, tells which version of the C runtime library (CRT) should be used.
-  For example, -DLLVM_USE_CRT_RELEASE=MT would statically link the CRT into the
-  LLVM tools and library. This is deprecated; use ``CMAKE_MSVC_RUNTIME_LIBRARY``
-  instead.
-
 **LLVM_USE_INTEL_JITEVENTS**:BOOL
   Enable building support for Intel JIT Events API. Defaults to OFF.