SDL_ttf: cmake: require C99 because of restrict keyword use.

SDL Commits
1 
From 94446745ef00117e8352dc80f3377b3790f7d57d Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Mon, 30 Sep 2024 21:15:00 +0300
Subject: [PATCH] cmake: require C99 because of restrict keyword use.

---
 CMakeLists.txt | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index db61f93d..edaf13c4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -125,6 +125,11 @@ if(SDLTTF_BUILD_SHARED_LIBS)
     target_link_libraries(${sdl3_ttf_target_name} PRIVATE SDL3::SDL3-shared)
 endif()
 sdl_add_warning_options(${sdl3_ttf_target_name} WARNING_AS_ERROR ${SDLTTF_WERROR})
+if ("c_std_99" IN_LIST CMAKE_C_COMPILE_FEATURES)
+    target_compile_features(${sdl3_ttf_target_name} PRIVATE c_std_99)
+else()
+    message(WARNING "target_compile_features does not know c_std_99 for C compiler")
+endif()
 if(WIN32 AND SDLTTF_BUILD_SHARED_LIBS)
     target_sources(${sdl3_ttf_target_name} PRIVATE
         src/version.rc