Check if libatomic can be linked (#12583)

* dont link with atomic on macos

* check if we can link with libatomic

configure.ac

@@ -1554,13 +1554,35 @@ if test "${enable_exporting_kinesis}" = "yes" -o \
     enable_cxx_linker="yes"
 fi
 
-# Unconditionally link with the libatomic since:
-# - if atomics are not needed, the library will be unused
-# - if atomics are needed, either atomics are fulfilled by the compiler builtins
-#   and the library is unused or the library is needed anyway.
-OPTIONAL_ATOMIC_LIBS="-latomic"
+# Try to unconditionally link with -latomic. If the compiler can satisfy
+# all the atomic ops with builtins then, the library will be left unused.
+# Otherwise, some ops will be covered by the compiler's intrinsics and some
+# will be picked up by the linker from -latomic. In the later case, if
+# -latomic is not available there will be a build failure, which would
+# have happened either way before this change.
+AC_LANG_PUSH([C++])
+
+AC_MSG_CHECKING(whether we can use -latomic)
+OLD_LIBS="${LIBS}"
+LIBS="-latomic"
+AC_LINK_IFELSE([AC_LANG_SOURCE([[
+  #include <atomic>
+  #include <cstdint>
+  std::atomic<std::int64_t> v;
+  int main() {
+    return v;
+  }
+]])], CAN_USE_LIBATOMIC=yes, CAN_USE_LIBATOMIC=no)
+LIBS="${OLD_LIBS}"
+AC_MSG_RESULT($CAN_USE_LIBATOMIC)
+
+if test "x$CAN_USE_LIBATOMIC" = xyes; then
+    OPTIONAL_ATOMIC_LIBS="-latomic"
+fi
 AC_SUBST([OPTIONAL_ATOMIC_LIBS])
 
+AC_LANG_POP([C++])
+
 AM_CONDITIONAL([ENABLE_CXX_LINKER], [test "${enable_cxx_linker}" = "yes"])
 
 AC_DEFINE_UNQUOTED([NETDATA_USER], ["${with_user}"], [use this user to drop privileged])