diff --git a/BasiliskII/src/Unix/configure.ac b/BasiliskII/src/Unix/configure.ac
index b201cd4e..c883ac56 100644
--- a/BasiliskII/src/Unix/configure.ac
+++ b/BasiliskII/src/Unix/configure.ac
@@ -315,6 +315,7 @@ if [[ "x$WANT_SDL" = "xyes" ]]; then
       WANT_SDL=no
       WANT_SDL_VIDEO=no
       WANT_SDL_AUDIO=no
+      SDL_SUPPORT="none"
     fi
   fi
   SDL_SUPPORT=`echo "$SDL_SUPPORT" | sed -e "s/^ //"`
diff --git a/SheepShaver/src/Unix/configure.ac b/SheepShaver/src/Unix/configure.ac
index 39f18115..006fe872 100644
--- a/SheepShaver/src/Unix/configure.ac
+++ b/SheepShaver/src/Unix/configure.ac
@@ -209,6 +209,7 @@ if [[ "x$WANT_SDL" = "xyes" ]]; then
       WANT_SDL=no
       WANT_SDL_VIDEO=no
       WANT_SDL_AUDIO=no
+      SDL_SUPPORT="none"
     fi
   fi
   SDL_SUPPORT=`echo "$SDL_SUPPORT" | sed -e "s/^ //"`