diff --git a/CMakeLists.txt b/CMakeLists.txt
index b2b9fa4eba1..4a90c9e74da 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,6 +10,7 @@ find_program(CCACHE_FOUND ccache)
 if(CCACHE_FOUND)
     set_property(GLOBAL PROPERTY RULE_LAUNCH_COMPILE ccache)
     set_property(GLOBAL PROPERTY RULE_LAUNCH_LINK ccache)
+    set(ENV{CCACHE_SLOPPINESS} pch_defines,time_macros)
 endif(CCACHE_FOUND)
 
 if(CMAKE_CXX_COMPILER_ID MATCHES "GNU")