diff --git a/src/libpsl-native/CMakeLists.txt b/src/libpsl-native/CMakeLists.txt
index e4f33cc..ce0e198 100644
--- a/src/libpsl-native/CMakeLists.txt
+++ b/src/libpsl-native/CMakeLists.txt
@@ -3,7 +3,7 @@ project(PSL-NATIVE)
 
 # Can't use add_compile_options with 2.8.11
 set(CMAKE_BUILD_TYPE "Release")
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wall -Werror -fstack-protector-strong -fpie -DFORTIFY_SOURCE=2 -O2")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wall -Werror -fstack-protector-strong -fpie -D_FORTIFY_SOURCE=2")
 
 if (${CMAKE_SYSTEM_NAME} MATCHES "Linux")
     set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -Wl,-z,relro,-z,now")
diff --git a/src/libpsl-native/arm.toolchain.cmake b/src/libpsl-native/arm.toolchain.cmake
index c2c6810..f514d40 100644
--- a/src/libpsl-native/arm.toolchain.cmake
+++ b/src/libpsl-native/arm.toolchain.cmake
@@ -1,7 +1,7 @@
 set(CMAKE_SYSTEM_NAME Linux)
 set(CMAKE_SYSTEM_VERSION 1)
 set(CMAKE_SYSTEM_PROCESSOR armv7l)
-set(CMAKE_CXX_COMPILER arm-linux-gnueabihf-g++ -fstack-protector-strong -fpie -DFORTIFY_SOURCE=2 -O2)
+set(CMAKE_CXX_COMPILER arm-linux-gnueabihf-g++ -fstack-protector-strong -fpie -D_FORTIFY_SOURCE=2)
 set(CMAKE_SHARED_LINKER_FLAGS "-Wl,-z,relro,-z,now")
 set(CMAKE_C_COMPILER arm-linux-gnueabihf-gcc)
 
diff --git a/src/libpsl-native/arm64.toolchain.cmake b/src/libpsl-native/arm64.toolchain.cmake
index 2bd02df..09a4d9d 100644
--- a/src/libpsl-native/arm64.toolchain.cmake
+++ b/src/libpsl-native/arm64.toolchain.cmake
@@ -1,7 +1,7 @@
 set(CMAKE_SYSTEM_NAME Linux)
 set(CMAKE_SYSTEM_VERSION 1)
 set(CMAKE_SYSTEM_PROCESSOR aarch64)
-set(CMAKE_CXX_COMPILER aarch64-linux-gnu-g++ -fstack-protector-strong -fpie -DFORTIFY_SOURCE=2 -O2)
+set(CMAKE_CXX_COMPILER aarch64-linux-gnu-g++ -fstack-protector-strong -fpie -D_FORTIFY_SOURCE=2)
 set(CMAKE_SHARED_LINKER_FLAGS "-Wl,-z,relro,-z,now")
 set(CMAKE_C_COMPILER aarch64-linux-gnu-gcc)