diff --git a/configure b/configure
index 7a1d08dc4a..9c726ebada 100755
--- a/configure
+++ b/configure
@@ -8,6 +8,9 @@
 CLICOLOR_FORCE= GREP_OPTIONS=
 unset CLICOLOR_FORCE GREP_OPTIONS
 
+# Don't allow CCACHE, if present, to use cached results of compile tests!
+export CCACHE_RECACHE=yes
+
 # Temporary directory used for files created while
 # configure runs. Since it is in the build directory
 # we can safely blow away any previous version of it
@@ -4412,6 +4415,7 @@ fi
 # check if ccache is interfering with
 # semantic analysis of macros
 
+unset CCACHE_CPP2
 ccache_cpp2=no
 cat > $TMPC << EOF
 static const int Z = 1;