Build the C extension with optimize options enabled (#230)

Author: BewareMyPower

CMakeLists.txt

@@ -25,6 +25,9 @@ set(CMAKE_PREFIX_PATH ${PROJECT_SOURCE_DIR}/pybind11/include ${CMAKE_PREFIX_PATH
 option(LINK_STATIC "Link against static libraries" OFF)
 MESSAGE(STATUS "LINK_STATIC:  " ${LINK_STATIC})
 
+if (NOT CMAKE_BUILD_TYPE)
+    set(CMAKE_BUILD_TYPE Release)
+endif ()
 MESSAGE(STATUS "CMAKE_BUILD_TYPE:  " ${CMAKE_BUILD_TYPE})
 set(THREADS_PREFER_PTHREAD_FLAG TRUE)
 find_package(Threads REQUIRED)