CMake: removed some unnecesary conditionals from add_clang_library.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@128483 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/CMakeLists.txt b/CMakeLists.txt
index a56d074..bc63cf8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -171,21 +171,12 @@
   if( LLVM_COMMON_DEPENDS )
     add_dependencies( ${name} ${LLVM_COMMON_DEPENDS} )
   endif( LLVM_COMMON_DEPENDS )
-  if( LLVM_USED_LIBS )
-    foreach(lib ${LLVM_USED_LIBS})
-      target_link_libraries( ${name} ${lib} )
-    endforeach(lib)
-  endif( LLVM_USED_LIBS )
-  if( LLVM_LINK_COMPONENTS )
-    llvm_config(${name} ${LLVM_LINK_COMPONENTS})
-  endif( LLVM_LINK_COMPONENTS )
-  if (LLVM_COMMON_LIBS)
-    target_link_libraries(${name} ${LLVM_COMMON_LIBS})
-  endif()
-  get_system_libs(llvm_system_libs)
-  if( llvm_system_libs )
-    target_link_libraries(${name} ${llvm_system_libs})
-  endif()
+
+  target_link_libraries( ${name} ${LLVM_USED_LIBS} )
+  llvm_config( ${name} ${LLVM_LINK_COMPONENTS} )
+  target_link_libraries( ${name} ${LLVM_COMMON_LIBS} )
+  link_system_libs( ${name} )
+
   add_dependencies(${name} ClangDiagnosticCommon)
   if(MSVC)
     get_target_property(cflag ${name} COMPILE_FLAGS)