[gn] port 1e65b76

Apparently DragonFly BSD and Solaris/illumos call these APIs
`pthread_get_name_np` / `pthread_set_name_np` (with an extra
underscore) instead of `pthread_getname_np` / `pthread_setname_np`.

Author: nico

llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn

@@ -97,6 +97,8 @@ write_cmake_config("config") {
     "HAVE_LIBPFM=",
     "HAVE_LIBPSAPI=",
     "HAVE_MALLCTL=",
+    "HAVE_PTHREAD_GET_NAME_NP=",
+    "HAVE_PTHREAD_SET_NAME_NP=",
     "HAVE_SIGNAL_H=1",
     "HAVE_SYS_STAT_H=1",
     "HAVE_SYS_TYPES_H=1",