[gn build] Port fdd089b

Author: llvmgnsyncbot

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

@@ -178,6 +178,7 @@ if (current_toolchain == default_toolchain) {
       "__algorithm/ranges_any_of.h",
       "__algorithm/ranges_binary_search.h",
       "__algorithm/ranges_clamp.h",
+      "__algorithm/ranges_contains.h",
       "__algorithm/ranges_copy.h",
       "__algorithm/ranges_copy_backward.h",
       "__algorithm/ranges_copy_if.h",