[CMake] Use LIST_SEPARATOR rather than escaping in ExternalProject_Add

Escaping ; in list arguments passed to ExternalProject_Add doesn't seem
to be working in newer versions of CMake (see
https://public.kitware.com/Bug/view.php?id=16137 for more details). Use
a custom LIST_SEPARATOR instead which is the officially supported way.

Differential Revision: https://reviews.llvm.org/D40257

llvm-svn: 319264

clang/CMakeLists.txt

@@ -653,7 +653,7 @@ if (CLANG_ENABLE_BOOTSTRAP)
   foreach(variableName ${variableNames})
     if(variableName MATCHES "^BOOTSTRAP_")
       string(SUBSTRING ${variableName} 10 -1 varName)
-      string(REPLACE ";" "\;" value "${${variableName}}")
+      string(REPLACE ";" "," value "${${variableName}}")
       list(APPEND PASSTHROUGH_VARIABLES
         -D${varName}=${value})
     endif()
@@ -669,7 +669,7 @@ if (CLANG_ENABLE_BOOTSTRAP)
       if("${${variableName}}" STREQUAL "")
         set(value "")
       else()
-        string(REPLACE ";" "\;" value ${${variableName}})
+        string(REPLACE ";" "," value "${${variableName}}")
       endif()
       list(APPEND PASSTHROUGH_VARIABLES
         -D${variableName}=${value})
@@ -697,6 +697,7 @@ if (CLANG_ENABLE_BOOTSTRAP)
     USES_TERMINAL_CONFIGURE 1
     USES_TERMINAL_BUILD 1
     USES_TERMINAL_INSTALL 1
+    LIST_SEPARATOR ,
     )
 
   # exclude really-install from main target