Forwarded: https://github.com/MariaDB/server/pull/1716
Author: Vicențiu Ciorbaru <vicentiu@mariadb.org>
Date:   Fri Dec 21 19:14:04 2018 +0200

   Link with libatomic to enable C11 atomics support

   Some architectures (mips) require libatomic to support proper
   atomic operations. Check first if support is available without
   linking, otherwise use the library.

   Original commit:
   Detect whether libatomic is needed rather than hard-coding for mips

   Fixes FTBFS on powerpc, since it needs libatomic too for C11 atomics,
   and possibly m68k.

   Contributors:
   James Cowgill <jcowgill@debian.org>
   Jessica Clarke <jrtc27@debian.org>

--- a/configure.cmake
+++ b/configure.cmake
@@ -866,7 +866,25 @@ int main()
   long long int *ptr= &var;
   return (int)__atomic_load_n(ptr, __ATOMIC_SEQ_CST);
 }"
-HAVE_GCC_C11_ATOMICS)
+HAVE_GCC_C11_ATOMICS_WITHOUT_LIBATOMIC)
+IF (HAVE_GCC_C11_ATOMICS_WITHOUT_LIBATOMIC)
+  SET(HAVE_GCC_C11_ATOMICS True)
+ELSE()
+  SET(OLD_CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
+  LIST(APPEND CMAKE_REQUIRED_LIBRARIES "atomic")
+  CHECK_CXX_SOURCE_COMPILES("
+  int main()
+  {
+    long long int var= 1;
+    long long int *ptr= &var;
+    return (int)__atomic_load_n(ptr, __ATOMIC_SEQ_CST);
+  }"
+  HAVE_GCC_C11_ATOMICS_WITH_LIBATOMIC)
+  IF(HAVE_GCC_C11_ATOMICS_WITH_LIBATOMIC)
+    SET(HAVE_GCC_C11_ATOMICS True)
+  ENDIF()
+  SET(CMAKE_REQUIRED_LIBRARIES ${OLD_CMAKE_REQUIRED_LIBRARIES})
+ENDIF()
 
 IF(WITH_VALGRIND)
   SET(HAVE_valgrind 1)
--- a/mysys/CMakeLists.txt
+++ b/mysys/CMakeLists.txt
@@ -168,6 +168,10 @@ TARGET_LINK_LIBRARIES(mysys dbug strings
  ${LIBNSL} ${LIBM} ${LIBRT} ${CMAKE_DL_LIBS} ${LIBSOCKET} ${LIBEXECINFO})
 DTRACE_INSTRUMENT(mysys)
 
+IF (HAVE_GCC_C11_ATOMICS_WITH_LIBATOMIC)
+  TARGET_LINK_LIBRARIES(mysys atomic)
+ENDIF()
+
 IF(HAVE_BFD_H)
   TARGET_LINK_LIBRARIES(mysys bfd)  
 ENDIF(HAVE_BFD_H)
--- a/sql/CMakeLists.txt
+++ b/sql/CMakeLists.txt
@@ -320,6 +320,10 @@ IF(WITH_MYSQLD_LDFLAGS)
      "${MYSQLD_LINK_FLAGS} ${WITH_MYSQLD_LDFLAGS}")
 ENDIF()
 
+IF (HAVE_GCC_C11_ATOMICS_WITH_LIBATOMIC)
+  TARGET_LINK_LIBRARIES(sql atomic)
+ENDIF()
+
 
 FIND_PACKAGE(BISON 2.0)