diff --git a/glicid/packages/cpp.scm b/glicid/packages/cpp.scm
index 444dcab..ca1786d 100644
--- a/glicid/packages/cpp.scm
+++ b/glicid/packages/cpp.scm
@@ -11,7 +11,7 @@
       ;; No tests.
     `(#:tests? #f
       ;; Build the shared library instead of a static one.
-      #:configure-flags `("-DBUILD_SHARED_LIBS=1 -DREPROC++=1")))
+      #:configure-flags `("-DBUILD_SHARED_LIBS=1 -DREPROC_DEVELOP=1")))