SDL_ttf: Fixed compiler warning when TTF_USE_SDF isn't available

SDL Commits
1 
From 42718c51dfd0dd5a6faef2b99e89d6a9e177c31c Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Wed, 7 Apr 2021 22:21:02 -0700
Subject: [PATCH] Fixed compiler warning when TTF_USE_SDF isn't available

---
 SDL_ttf.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/SDL_ttf.c b/SDL_ttf.c
index adb1eda..7cf09c3 100644
--- a/SDL_ttf.c
+++ b/SDL_ttf.c
@@ -394,6 +394,8 @@ static SDL_INLINE void BG_Blended_Color(const TTF_Image *image, Uint32 *destinat
     }
 }
 
+#if TTF_USE_SDF
+
 /* Blended Opaque SDF */
 static SDL_INLINE void BG_Blended_Opaque_SDF(const TTF_Image *image, Uint32 *destination, Sint32 srcskip, Uint32 dstskip)
 {
@@ -450,6 +452,8 @@ static SDL_INLINE void BG_Blended_SDF(const TTF_Image *image, Uint32 *destinatio
     }
 }
 
+#endif /* TTF_USE_SDF */
+
 /* Blended Opaque */
 static SDL_INLINE void BG_Blended_Opaque(const TTF_Image *image, Uint32 *destination, Sint32 srcskip, Uint32 dstskip)
 {