commit f6b5ca72c646e60d3a370eccd7847e624aa17b26
Author: Norvald H. Ryeng <norvald@ryeng.name>
Date:   Tue Mar 22 19:49:46 2016 +0100

    Link with libatomic when necessary
    
    When lock free instructions are not available, GCC will expect
    them to be implemented by an atomics library. Check if __sync or
    __atomic symbols are implemented by a library and link with it if
    they are.
    
    The symbols used in the checks are chosen randomly. If some
    operations are built in and others are implemented by libatomic,
    it may be that just these symbols happen to be built in. In that
    case, more checks should be added for symbols that aren't built
    in.

diff --git a/configure.cmake b/configure.cmake
index 32829f9..1a2df09 100644
--- a/configure.cmake
+++ b/configure.cmake
@@ -314,9 +314,13 @@ IF(UNIX)
     MY_SEARCH_LIBS(clock_gettime rt LIBRT)
   ENDIF()
   MY_SEARCH_LIBS(timer_create rt LIBRT)
+  MY_SEARCH_LIBS(__sync_fetch_and_add_8 atomic LIBATOMIC)
+  IF(NOT LIBATOMIC)
+    MY_SEARCH_LIBS(__atomic_load_8 atomic LIBATOMIC)
+  ENDIF()
 
   SET(CMAKE_REQUIRED_LIBRARIES 
-    ${LIBM} ${LIBNSL} ${LIBBIND} ${LIBCRYPT} ${LIBSOCKET} ${LIBDL} ${CMAKE_THREAD_LIBS_INIT} ${LIBRT})
+    ${LIBM} ${LIBNSL} ${LIBBIND} ${LIBCRYPT} ${LIBSOCKET} ${LIBDL} ${CMAKE_THREAD_LIBS_INIT} ${LIBRT} ${LIBATOMIC})
   # Need explicit pthread for gcc -fsanitize=address
   IF(CMAKE_C_FLAGS MATCHES "-fsanitize=")
     SET(CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES} pthread)