diff --git a/CMakeLists.txt b/CMakeLists.txt
index cdc6d73..cebacaa 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,5 @@
 project(libucore C)
-cmake_minimum_required(VERSION 3.0.0)
+cmake_minimum_required(VERSION 2.8.0)
 
 execute_process(COMMAND git -C ${CMAKE_SOURCE_DIR} describe --abbrev=5 --dirty --always OUTPUT_VARIABLE version_revision  WORKING_DIRECTORY ${PROJECT_SOURCE_DIR} OUTPUT_STRIP_TRAILING_WHITESPACE)
 execute_process(COMMAND hostname OUTPUT_VARIABLE build_host OUTPUT_STRIP_TRAILING_WHITESPACE)
@@ -11,7 +11,7 @@ set(libucore_VERSION ${libucore_VERSION_MAJOR}.${libucore_VERSION_MINOR}.${libuc
 
 set(CMAKE_VERBOSE_MAKEFILE ON)
 
-set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -Wundef -Wcast-qual -Wshadow -Wcast-align -pipe -Wno-unused-parameter -Werror=implicit-function-declaration -Winit-self -pthread")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu99 -Wall -Wextra -Wundef -Wcast-qual -Wshadow -Wcast-align -pipe -Wno-unused-parameter -Werror=implicit-function-declaration -Winit-self -pthread")
 add_definitions(-D_FILE_OFFSET_BITS=64)
 set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -O2 -pthread")