diff --git a/lib/Makefile.am b/lib/Makefile.am
index 209e24511f..b8aaadab80 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -86,7 +86,7 @@ if USE_UNITY
 # Keep these separate to avoid duplicate definitions when linking libtests
 # in static mode.
 curl_EXCLUDE = curl_threads.c timediff.c warnless.c
-if DEBUGBUILD
+if CURLDEBUG
 # We must compile these sources separately to avoid memdebug.h redefinitions
 # applying to them.
 curl_EXCLUDE += memdebug.c curl_multibyte.c
diff --git a/src/Makefile.am b/src/Makefile.am
index 59406def6a..dcf1e371c8 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -71,7 +71,7 @@ CLEANFILES =
 
 if USE_UNITY
 curl_EXCLUDE =
-if DEBUGBUILD
+if CURLDEBUG
 # We must compile this source separately to avoid memdebug.h redefinitions
 # applying to them.
 curl_EXCLUDE += ../lib/curl_multibyte.c