[CMake][compiler-rt] Don't load LLVM config in the runtimes build

LLVM runtimes build already loads the LLVM config and sets all
appropriate variables, no need to do it again.

Differential Revision: https://reviews.llvm.org/D137870

compiler-rt/CMakeLists.txt

@@ -79,7 +79,9 @@ if (COMPILER_RT_STANDALONE_BUILD)
   set(CMAKE_CXX_STANDARD_REQUIRED YES)
   set(CMAKE_CXX_EXTENSIONS NO)
 
-  load_llvm_config()
+  if (NOT LLVM_RUNTIMES_BUILD)
+    load_llvm_config()
+  endif()
   if (TARGET intrinsics_gen)
     # Loading the llvm config causes this target to be imported so place it
     # under the appropriate folder in an IDE.

compiler-rt/lib/builtins/CMakeLists.txt

@@ -25,7 +25,9 @@ if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
   include(base-config-ix)
   include(CompilerRTUtils)
 
-  load_llvm_config()
+  if (NOT LLVM_RUNTIMES_BUILD)
+    load_llvm_config()
+  endif()
   construct_compiler_rt_default_triple()
 
   include(SetPlatformToolchainTools)

runtimes/CMakeLists.txt

@@ -54,6 +54,7 @@ if (NOT LLVM_BINARY_DIR)
 endif()
 if (NOT LLVM_FOUND)
   set(LLVM_TOOLS_BINARY_DIR ${LLVM_BINARY_DIR}/bin)
+  set(LLVM_INCLUDE_DIR ${CMAKE_CURRENT_BINARY_DIR}/include)
   set(LLVM_LIBRARY_DIR ${CMAKE_CURRENT_BINARY_DIR}/lib)
 endif()