CMake: Use libdl only when available. Fixes build on FreeBSD.

llvm-svn: 72311

cmake/config-ix.cmake

@@ -42,6 +42,7 @@ check_include_file(windows.h HAVE_WINDOWS_H)
 # library checks
 include(CheckLibraryExists)
 check_library_exists(pthread pthread_create "" HAVE_LIBPTHREAD)
+check_library_exists(dl dlopen "" HAVE_LIBDL)
 
 # function checks
 include(CheckSymbolExists)

cmake/modules/AddLLVM.cmake

@@ -33,7 +33,9 @@ macro(add_llvm_executable name)
     if( MINGW )
       target_link_libraries(${name} imagehlp psapi)
     elseif( CMAKE_HOST_UNIX )
-      target_link_libraries(${name} dl)
+      if( HAVE_LIBDL )
+	target_link_libraries(${name} dl)
+      endif()
       if( LLVM_ENABLE_THREADS AND HAVE_LIBPTHREAD )
 	target_link_libraries(${name} pthread)
       endif()