SDL: Treat the QNX compiler as GCC for using atomics

SDL Commits
1 
From 292b80a13ad9e8df748a8c630d89c7719175d24d Mon Sep 17 00:00:00 2001
From: Elad Lahav <[EMAIL REDACTED]>
Date: Sat, 7 Jan 2023 06:52:19 -0500
Subject: [PATCH] Treat the QNX compiler as GCC for using atomics

---
 CMakeLists.txt | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index a4d963263bba..bd8cc234df29 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -201,7 +201,7 @@ else()
   set(SDL_ASSEMBLY_DEFAULT FALSE)
 endif()
 
-if(USE_GCC OR USE_CLANG OR USE_INTELCC)
+if(USE_GCC OR USE_CLANG OR USE_INTELCC OR USE_QCC)
   set(OPT_DEF_GCC_ATOMICS ON)
 endif()
 
@@ -545,7 +545,7 @@ if(NOT SDL_FOREGROUNDING_SIGNAL STREQUAL "OFF")
 endif()
 
 # Compiler option evaluation
-if(USE_GCC OR USE_CLANG OR USE_INTELCC)
+if(USE_GCC OR USE_CLANG OR USE_INTELCC OR USE_QCC)
   # Check for -Wall first, so later things can override pieces of it.
   # Note: clang-cl treats -Wall as -Weverything (which is very loud),
   #       /W3 as -Wall, and /W4 as -Wall -Wextra.  So: /W3 is enough.