[gn build] Port 07ad928

Author: llvmgnsyncbot

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

@@ -269,6 +269,7 @@ if (current_toolchain == default_toolchain) {
       "__algorithm/simd_utils.h",
       "__algorithm/sort.h",
       "__algorithm/sort_heap.h",
+      "__algorithm/specialized_algorithms.h",
       "__algorithm/stable_partition.h",
       "__algorithm/stable_sort.h",
       "__algorithm/swap_ranges.h",