only use -flto when supported, quenched policy warnings
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2fa32e8..c77ab8f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -27,14 +27,23 @@
find_package(PythonLibs ${PYBIND11_PYTHON_VERSION} REQUIRED)
find_package(PythonInterp ${PYBIND11_PYTHON_VERSION} REQUIRED)
-if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang" OR "${CMAKE_CXX_COMPILER_ID}" MATCHES "GNU")
+include(CheckCXXCompilerFlag)
+
+if (CMAKE_CXX_COMPILER_ID MATCHES "Clang" OR CMAKE_CXX_COMPILER_ID MATCHES "GNU")
# Enable C++11 mode on C++ / Clang
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
# Enable link time optimization and set the default symbol
# visibility to hidden (very important to obtain small binaries)
if (NOT ${U_CMAKE_BUILD_TYPE} MATCHES DEBUG)
- set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fvisibility=hidden -flto")
+ # Default symbol visibility
+ set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fvisibility=hidden")
+
+ # Check for Link Time Optimization support
+ CHECK_CXX_COMPILER_FLAG("-flto" HAS_LTO_FLAG)
+ if (HAS_LTO_FLAG)
+ set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -flto")
+ endif()
endif()
endif()