diff --git a/CMakeLists.txt b/CMakeLists.txt
index 062756e..4e13cd1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,7 +3,7 @@ project(auth_service LANGUAGES C)
 
 set(CMAKE_C_STANDARD 23)
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
-set(CMAKE_C_FLAGS "-ffunction-sections -fdata-sections")
+set(CMAKE_C_FLAGS "-ffunction-sections -fdata-sections -DMG_TLS=MG_TLS_OPENSSL")
 if (APPLE)
 elseif (UNIX)
     set(CMAKE_EXE_LINKER_FLAGS "-Wl,--gc-sections")
diff --git a/meson.build b/meson.build
index 028b0d6..d17f551 100644
--- a/meson.build
+++ b/meson.build
@@ -1,7 +1,7 @@
 project('auth_service', 'c', default_options: ['c_std=gnu2x'])
 include_dirs = include_directories('src', 'src/lib')
 deps = [dependency('openssl')]
-extra_c_args = ['-ffunction-sections', '-fdata-sections']
+extra_c_args = ['-ffunction-sections', '-fdata-sections', '-DMG_TLS=MG_TLS_OPENSSL']
 extra_c_link_args = []
 system = host_machine.system()
 if system == 'linux'