cmake: add qnx support

Co-authored-by: elahav <elahav@users.noreply.github.com>

CMakeLists.txt

@@ -227,11 +227,13 @@ elseif(MSVC_VERSION GREATER 1400) # VisualStudio 8.0+
 elseif(CMAKE_C_COMPILER_ID MATCHES "^Intel$")
   set(OPT_DEF_ASM TRUE)
   set(USE_INTELCC TRUE)
+elseif(CMAKE_C_COMPILER_ID MATCHES "QCC")
+  set(USE_QCC TRUE)
 else()
   set(OPT_DEF_ASM 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()
 
@@ -569,7 +571,7 @@ 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.
@@ -1428,6 +1430,12 @@ elseif(UNIX AND NOT APPLE AND NOT RISCOS AND NOT HAIKU)
         file(GLOB AIX_AUDIO_SOURCES ${SDL2_SOURCE_DIR}/src/audio/paudio/*.c)
         list(APPEND SOURCE_FILES ${AIX_AUDIO_SOURCES})
         set(HAVE_SDL_AUDIO TRUE)
+    elseif(QNX)
+        set(SDL_AUDIO_DRIVER_QSA 1)
+        file(GLOB QSA_AUDIO_SOURCES ${SDL2_SOURCE_DIR}/src/audio/qsa/*.c)
+        list(APPEND SOURCE_FILES ${QSA_AUDIO_SOURCES})
+        list(APPEND EXTRA_LIBS asound)
+        set(HAVE_SDL_AUDIO TRUE)
     endif()
     CheckOSS()
     CheckALSA()
@@ -1459,6 +1467,7 @@ elseif(UNIX AND NOT APPLE AND NOT RISCOS AND NOT HAIKU)
       set(SDL_VIDEO_VULKAN 1)
       set(HAVE_VULKAN TRUE)
     endif()
+    CheckQNXScreen()
   endif()
 
   if(UNIX)
@@ -1709,6 +1718,13 @@ elseif(UNIX AND NOT APPLE AND NOT RISCOS AND NOT HAIKU)
     set(HAVE_RPATH TRUE)
   endif()
 
+  if(QNX)
+    # QNX's *printf() family generates a SIGSEGV if NULL is passed for a string
+    # specifier (on purpose), but SDL expects "(null)". Use the built-in
+    # implementation.
+    set(HAVE_VSNPRINTF 0)
+    set(USE_POSIX_SPAWN 1)
+  endif()
 elseif(WINDOWS)
   find_program(WINDRES windres)
 

cmake/sdlchecks.cmake

@@ -905,6 +905,22 @@ macro(CheckOpenGLES)
   endif()
 endmacro()
 
+# Requires:
+# - EGL
+macro(CheckQNXScreen)
+  if(QNX AND HAVE_OPENGL_EGL)
+    check_c_source_compiles("
+        #include <screen/screen.h>
+        int main (int argc, char** argv) { return 0; }" HAVE_QNX_SCREEN)
+    if(HAVE_QNX_SCREEN)
+      set(SDL_VIDEO_DRIVER_QNX 1)
+      file(GLOB QNX_VIDEO_SOURCES ${SDL2_SOURCE_DIR}/src/video/qnx/*.c)
+      list(APPEND SOURCE_FILES ${QNX_VIDEO_SOURCES})
+      list(APPEND EXTRA_LIBS screen EGL)
+    endif()
+  endif()
+endmacro()
+
 # Requires:
 # - nada
 # Optional:
@@ -955,6 +971,8 @@ macro(CheckPTHREAD)
     elseif(EMSCRIPTEN)
       set(PTHREAD_CFLAGS "-D_REENTRANT -pthread")
       set(PTHREAD_LDFLAGS "-pthread")
+    elseif(QNX)
+      # pthread support is baked in
     else()
       set(PTHREAD_CFLAGS "-D_REENTRANT")
       set(PTHREAD_LDFLAGS "-lpthread")

cmake/sdlplatform.cmake

@@ -28,6 +28,8 @@ macro(SDL_DetectCMakePlatform)
       set(SDL_CMAKE_PLATFORM AIX)
     elseif(CMAKE_SYSTEM_NAME MATCHES "Minix.*")
       set(SDL_CMAKE_PLATFORM MINIX)
+    elseif(CMAKE_SYSTEM_NAME MATCHES "QNX")
+      set(SDL_CMAKE_PLATFORM QNX)
     endif()
   elseif(APPLE)
     if(CMAKE_SYSTEM_NAME MATCHES ".*Darwin.*")