[CMake] Check if passthrough variables are defined

Checking if they evaluate to true cases prevents passing values that evaluate to false cases. Instead we should check if the variables are defined.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@282122 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 12f79df6e229846fb38d10648aea33c3ef787a7e..9b7322e279be53f76fba0094e7ae8a4fc110e2ca 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -610,7 +610,7 @@ if (CLANG_ENABLE_BOOTSTRAP)
 
   # Populate the passthrough variables
   foreach(variableName ${CLANG_BOOTSTRAP_PASSTHROUGH} ${_BOOTSTRAP_DEFAULT_PASSTHROUGH})
-    if(${variableName})
+    if(DEFINED ${variableName})
       string(REPLACE ";" "\;" value ${${variableName}})
       list(APPEND PASSTHROUGH_VARIABLES
         -D${variableName}=${value})