diff --git a/libao-async-ffi.rkt b/libao-async-ffi.rkt
index aa3cda9..a3ba906 100644
--- a/libao-async-ffi.rkt
+++ b/libao-async-ffi.rkt
@@ -18,7 +18,8 @@
          )
 
 (define lib (get-lib '("ao-play-async" "libao-play-async") '(#f)))
-(define-ffi-definer define-libao-async lib)
+(define-ffi-definer define-libao-async lib
+  #:default-make-fail make-not-available)
 
 (define _libao-async-handle-pointer (_cpointer 'ao-async-handle))
 
diff --git a/libao-ffi.rkt b/libao-ffi.rkt
index e204b16..783f247 100644
--- a/libao-ffi.rkt
+++ b/libao-ffi.rkt
@@ -27,7 +27,8 @@
 
 
 (define ao_lib (get-lib '("libao") '("5" "4" "3" #f)))
-(define-ffi-definer define-libao ao_lib)
+(define-ffi-definer define-libao ao_lib
+    #:default-make-fail make-not-available)
 
 (define _libao-pointer (_cpointer 'ao_device))
 (define-cstruct _ao_sample_format (
diff --git a/libflac-ffi.rkt b/libflac-ffi.rkt
index cf0b567..7afb243 100644
--- a/libflac-ffi.rkt
+++ b/libflac-ffi.rkt
@@ -16,7 +16,8 @@
 
 
 (define lib (get-lib '("libFLAC") '(#f)))
-(define-ffi-definer define-libflac lib)
+(define-ffi-definer define-libflac lib
+  #:default-make-fail make-not-available)
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Some FLAC Constants
diff --git a/taglib-ffi.rkt b/taglib-ffi.rkt
index ba9bd7f..069bba3 100644
--- a/taglib-ffi.rkt
+++ b/taglib-ffi.rkt
@@ -68,7 +68,9 @@
 
 (define libtag (get-lib '("tag" "libtag") '("2" #f)))
 (define libtag_c (get-lib '("tag_c" "libtag_c") '("#2" #f)))
-(define-ffi-definer define-tag-c-lib libtag_c)
+
+(define-ffi-definer define-tag-c-lib libtag_c
+  #:default-make-fail make-not-available)
 
 (define TagLib_File_Type
   (_enum '(