cmake: Fix static SDL3 on Linux

Author: allkern

CMakeLists.txt

@@ -8,14 +8,20 @@ set(WIN_ICON ${CMAKE_CURRENT_SOURCE_DIR}/res/iris.rc)
 set(CMAKE_OSX_ARCHITECTURES "x86_64;arm64")
 set(CMAKE_OSX_DEPLOYMENT_TARGET "10.15")
 set(OSX_ICON ${CMAKE_CURRENT_SOURCE_DIR}/res/iris.icns)
-set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -DSDL_STATIC=ON")
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DSDL_STATIC=ON")
+
 set_source_files_properties(${OSX_ICON} PROPERTIES MACOSX_PACKAGE_LOCATION "Resources")
 
 if (CMAKE_SYSTEM_PROCESSOR MATCHES "AMD64")
     target_compile_options(iris PRIVATE -D_EE_USE_INTRINSICS)
 endif()
 
+# Statically link SDL3 for Linux targets
+set(SDL_STATIC ON)
+
+if (CMAKE_SYSTEM_NAME MATCHES "Linux")
+    set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+endif()
+
 # if (CMAKE_CXX_COMPILER_ID MATCHES "MSVC")
 #     add_custom_command(
 #         OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/main_data.c"