diff --git a/src/stb_image.h b/src/stb_image.h
index 5186d4d..2c4bb9c 100644
--- a/src/stb_image.h
+++ b/src/stb_image.h
@@ -8,7 +8,7 @@ unsigned char * stbi_zlib_compress(unsigned char *data, int data_len, int *out_l
 
    stb_image - v2.23 - public domain image loader - http://nothings.org/stb_image.h
 */
-const char *stbi__g_failure_reason;
+extern const char *stbi__g_failure_reason;
 
 enum
 {
@@ -68,6 +68,7 @@ void *stbi__png_load(stbi__context *s, int *x, int *y, int *comp, int req_comp,
 unsigned char *stbi_write_png_to_mem(const unsigned char *pixels, int stride_bytes, int x, int y, int n, int *out_len);
 
 #ifdef STB_IMAGE_IMPLEMENTATION
+const char *stbi__g_failure_reason;
 
 _inline static unsigned char stbi__get8(stbi__context *s)
 {