haiku: get cmake bootstrap working

build.zig

@@ -747,6 +747,9 @@ fn addCmakeCfgOptionsToExe(
                 try addCxxKnownPath(b, cfg, exe, b.fmt("libstdc++.{s}", .{lib_suffix}), null, need_cpp_includes);
                 try addCxxKnownPath(b, cfg, exe, b.fmt("libgcc_eh.{s}", .{lib_suffix}), null, need_cpp_includes);
             },
+            .haiku => {
+                try addCxxKnownPath(b, cfg, exe, b.fmt("libstdc++.{s}", .{lib_suffix}), null, need_cpp_includes);
+            },
             else => {},
         }
     }

lib/std/Target.zig

@@ -2740,6 +2740,13 @@ pub fn is_libc_lib_name(target: std.Target, name: []const u8) bool {
             return true;
     }
 
+    if (target.os.tag == .haiku) {
+        if (eqlIgnoreCase(ignore_case, name, "root"))
+            return true;
+        if (eqlIgnoreCase(ignore_case, name, "network"))
+            return true;
+    }
+
     return false;
 }