[runtimes] Use llvm-libtool-darwin for runtimes build

It's full featured now and we can use it for the runtimes build instead
of relying on an external libtool, which means the CMAKE_HOST_APPLE
restriction serves no purpose either now. Restrict llvm-lipo to Darwin
targets while I'm here, since it's only needed there.

Reviewed By: phosek

Differential Revision: https://reviews.llvm.org/D86367

compiler-rt/CMakeLists.txt

@@ -112,7 +112,7 @@ if (COMPILER_RT_STANDALONE_BUILD)
   endif()
 
   # Ensure that fat libraries are built correctly on Darwin
-  if(CMAKE_HOST_APPLE AND APPLE)
+  if(APPLE)
     include(UseLibtool)
   endif()
 

compiler-rt/lib/builtins/CMakeLists.txt

@@ -20,7 +20,7 @@ if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
   if(APPLE)
     include(CompilerRTDarwinUtils)
   endif()
-  if(CMAKE_HOST_APPLE AND APPLE)
+  if(APPLE)
     include(UseLibtool)
   endif()
   include(AddCompilerRT)

llvm/cmake/modules/LLVMExternalProjectUtils.cmake

@@ -53,8 +53,10 @@ function(llvm_ExternalProject_Add name source_dir)
   endforeach()
 
   if(NOT ARG_TOOLCHAIN_TOOLS)
-    set(ARG_TOOLCHAIN_TOOLS clang lld llvm-ar llvm-lipo llvm-ranlib llvm-nm llvm-objdump)
-    if(NOT _cmake_system_name STREQUAL Darwin)
+    set(ARG_TOOLCHAIN_TOOLS clang lld llvm-ar llvm-ranlib llvm-nm llvm-objdump)
+    if(_cmake_system_name STREQUAL Darwin)
+      list(APPEND ARG_TOOLCHAIN_TOOLS llvm-libtool-darwin llvm-lipo)
+    else()
       # TODO: These tools don't fully support Mach-O format yet.
       list(APPEND ARG_TOOLCHAIN_TOOLS llvm-objcopy llvm-strip)
     endif()
@@ -144,6 +146,9 @@ function(llvm_ExternalProject_Add name source_dir)
     if(llvm-ar IN_LIST TOOLCHAIN_TOOLS)
       list(APPEND compiler_args -DCMAKE_AR=${LLVM_RUNTIME_OUTPUT_INTDIR}/llvm-ar${CMAKE_EXECUTABLE_SUFFIX})
     endif()
+    if(llvm-libtool-darwin IN_LIST TOOLCHAIN_TOOLS)
+      list(APPEND compiler_args -DCMAKE_LIBTOOL=${LLVM_RUNTIME_OUTPUT_INTDIR}/llvm-libtool-darwin${CMAKE_EXECUTABLE_SUFFIX})
+    endif()
     if(llvm-lipo IN_LIST TOOLCHAIN_TOOLS)
       list(APPEND compiler_args -DCMAKE_LIPO=${LLVM_RUNTIME_OUTPUT_INTDIR}/llvm-lipo${CMAKE_EXECUTABLE_SUFFIX})
     endif()