From d43fbadd2eebf8ad7886dd22c8ee94d3d1613c08 Mon Sep 17 00:00:00 2001
From: David Thompson <dthompson2@worcester.edu>
Date: Sat, 25 Sep 2021 13:20:20 -0400
Subject: freetype: Support old versions that do not have FT_Error_String.

---
 chickadee/freetype.scm | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/chickadee/freetype.scm b/chickadee/freetype.scm
index 73c0791..de93d00 100644
--- a/chickadee/freetype.scm
+++ b/chickadee/freetype.scm
@@ -83,8 +83,14 @@
 (define FT_LOAD_COMPUTE_METRICS             32768)
 (define FT_LOAD_BITMAP_METRICS_ONLY         65536)
 
-(define-foreign ft-error-string
-  '* "FT_Error_String" (list int))
+;; FT_Error_String only exists in libfreetype 2.10.0+, and we wish to
+;; support older versions so we stub out the function when it doesn't
+;; exist.
+(define ft-error-string
+  (or (false-if-exception (freetype-func '* "FT_Error_String" (list int)))
+      (lambda (error-code)
+        (string->pointer
+         (string-append "error code " (number->string error-code))))))
 
 (define-foreign ft-init-freetype
   int "FT_Init_FreeType" '(*))
-- 
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