CMake: Option for enabling/disabling threads.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@59565 91177308-0d34-0410-b5e6-96231b3b80d8

CMakeLists.txt

@@ -50,6 +50,8 @@ else( MSVC )
     CACHE STRING "Semicolon-separated list of targets to build, or \"all\".")
 endif( MSVC )
 
+option(LLVM_ENABLE_THREADS "Use threads if available." ON)
+
 if( LLVM_TARGETS_TO_BUILD STREQUAL "all" )
   set( LLVM_TARGETS_TO_BUILD ${LLVM_ALL_TARGETS} )
 endif()

cmake/config-ix.cmake

@@ -93,8 +93,17 @@ endif( NOT MSVC )
 # FIXME: Signal handler return type, currently hardcoded to 'void'
 set(RETSIGTYPE void)
 
-# Disable multithreading for now
-set(ENABLE_THREADS 0)
+if( LLVM_ENABLE_THREADS )
+  if( HAVE_PTHREAD_H OR WIN32 )
+    set(ENABLE_THREADS 1)
+  endif()
+endif()
+
+if( ENABLE_THREADS )
+  message(STATUS "Threads enabled.")
+else( ENABLE_THREADS )
+  message(STATUS "Threads disabled.")
+endif()
 
 configure_file(
   ${LLVM_MAIN_INCLUDE_DIR}/llvm/Config/config.h.cmake