Later versions of gcc on some architectures push atomic functions
out into a separate atomic library; add a check to see when this
is required and add it to LIBS if need be.
Specifically the problem was observed on GCC 4.8.2 on powerpc
architecture for Ubuntu 14.04:
https://launchpadlibrarian.net/
155235096/buildlog_ubuntu-trusty-powerpc.openvswitch_2.0.0-0ubuntu1_FAILEDTOBUILD.txt.gz
Signed-off-by: James Page <james.page@ubuntu.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
OVS_CHECK_GNU_MAKE
OVS_CHECK_CACHE_TIME
OVS_CHECK_TLS
OVS_CHECK_GNU_MAKE
OVS_CHECK_CACHE_TIME
OVS_CHECK_TLS
OVS_CHECK_GCC4_ATOMICS
OVS_CHECK_ATOMIC_ALWAYS_LOCK_FREE(1)
OVS_CHECK_ATOMIC_ALWAYS_LOCK_FREE(2)
OVS_CHECK_GCC4_ATOMICS
OVS_CHECK_ATOMIC_ALWAYS_LOCK_FREE(1)
OVS_CHECK_ATOMIC_ALWAYS_LOCK_FREE(2)
+dnl OVS_CHECK_ATOMIC_LIBS
+dnl
+dnl Check to see if -latomic is need for GCC atomic built-ins.
+AC_DEFUN([OVS_CHECK_ATOMIC_LIBS],
+ [AC_SEARCH_LIBS([__atomic_load_8], [atomic])])
+
dnl OVS_CHECK_GCC4_ATOMICS
dnl
dnl Checks whether the compiler and linker support GCC 4.0+ atomic built-ins.
dnl OVS_CHECK_GCC4_ATOMICS
dnl
dnl Checks whether the compiler and linker support GCC 4.0+ atomic built-ins.