diff --git a/Source/JavaScriptCore/ChangeLog b/Source/JavaScriptCore/ChangeLog
index 34b5ccc..32a4868 100644
--- a/Source/JavaScriptCore/ChangeLog
+++ b/Source/JavaScriptCore/ChangeLog
@@ -1,3 +1,15 @@
+2013-02-27  Simon Hausmann  <simon.hausmann@digia.com>
+
+        [Qt][Mac] Fix massive parallel builds
+
+        Reviewed by NOBODY (OOPS!).
+
+        There exists a race condition that LLIntDesiredOffsets.h is written to
+        by two parllel instances of the ruby script. This patch ensures that similar to the output file,
+        the generated file is also prefixed according to the build configuration.
+
+        * LLIntOffsetsExtractor.pro:
+
 2013-02-26  Filip Pizlo  <fpizlo@apple.com>
 
         DFG OSR exit doesn't know which virtual register to use for the last result register for post_inc and post_dec
diff --git a/Source/JavaScriptCore/LLIntOffsetsExtractor.pro b/Source/JavaScriptCore/LLIntOffsetsExtractor.pro
index b6673b5..685ac2a 100644
--- a/Source/JavaScriptCore/LLIntOffsetsExtractor.pro
+++ b/Source/JavaScriptCore/LLIntOffsetsExtractor.pro
@@ -8,8 +8,6 @@
 TEMPLATE = app
 TARGET = LLIntOffsetsExtractor
 
-macx: DESTDIR = $$targetSubDir()
-
 debug_and_release {
     CONFIG += force_build_all
     CONFIG += build_all
@@ -59,6 +57,12 @@ llint.commands = ruby $$llint.script ${QMAKE_FILE_NAME} ${QMAKE_FILE_OUT}
 llint.CONFIG += no_link
 QMAKE_EXTRA_COMPILERS += llint
 
+macx {
+    DESTDIR = $$targetSubDir()
+    llint.output = $$activeBuildConfig()/$$llint.output
+    INCLUDEPATH += $$activeBuildConfig()
+}
+
 # Compilation of this file will automatically depend on LLIntDesiredOffsets.h
 # due to qmake scanning the source file for header dependencies.
 SOURCES = llint/LLIntOffsetsExtractor.cpp