In clang/libcxx 19, treatment of std::char_traits was tightened
down - e.g. no generic (std::char_traits<unsigned char> etc) traits
are not implemented anymore - which resulted in fallout in HEAD
after the import of llvm/libcxx 19.
jkim@ collected the neccessary patches from
https://github.com/rnpgp/rnp/commit/20419f739f632fb30666650544f0055e8d4f1afa
https://github.com/rnpgp/sexpp/commit/46744a14ffc235330bb99cebfaf294829c31bba4

--- comm/third_party/rnp/src/lib/types.h.orig	2024-10-25 23:29:32 UTC
+++ comm/third_party/rnp/src/lib/types.h
@@ -95,9 +95,6 @@ class id_str_pair {
     static int         lookup(const id_str_pair           pair[],
                               const std::vector<uint8_t> &bytes,
                               int                         notfound = 0);
-    static int         lookup(const id_str_pair                 pair[],
-                              const std::basic_string<uint8_t> &bytes,
-                              int                               notfound = 0);
 };
 
 /** pgp_fingerprint_t */
--- comm/third_party/rnp/src/lib/utils.cpp.orig	2024-10-25 23:29:32 UTC
+++ comm/third_party/rnp/src/lib/utils.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, [Ribose Inc](https://www.ribose.com).
+ * Copyright (c) 2021, 2024 [Ribose Inc](https://www.ribose.com).
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -53,21 +53,6 @@ id_str_pair::lookup(const id_str_pair pair[], const st
 
 int
 id_str_pair::lookup(const id_str_pair pair[], const std::vector<uint8_t> &bytes, int notfound)
-{
-    while (pair && pair->str) {
-        if ((strlen(pair->str) == bytes.size()) &&
-            !memcmp(pair->str, bytes.data(), bytes.size())) {
-            return pair->id;
-        }
-        pair++;
-    }
-    return notfound;
-}
-
-int
-id_str_pair::lookup(const id_str_pair                 pair[],
-                    const std::basic_string<uint8_t> &bytes,
-                    int                               notfound)
 {
     while (pair && pair->str) {
         if ((strlen(pair->str) == bytes.size()) &&
--- comm/third_party/rnp/src/librekey/key_store_g10.cpp.orig	2024-10-25 23:29:32 UTC
+++ comm/third_party/rnp/src/librekey/key_store_g10.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2022, [Ribose Inc](https://www.ribose.com).
+ * Copyright (c) 2017-2024, [Ribose Inc](https://www.ribose.com).
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -312,12 +312,12 @@ read_curve(const sexp_list_t *list, const std::string 
 
     const auto &bytes = data->get_string();
     pgp_curve_t curve = static_cast<pgp_curve_t>(
-      id_str_pair::lookup(g10_curve_aliases, data->get_string(), PGP_CURVE_UNKNOWN));
+      id_str_pair::lookup(g10_curve_aliases, (const char *) bytes.data(), PGP_CURVE_UNKNOWN));
     if (curve != PGP_CURVE_UNKNOWN) {
         key.curve = curve;
         return true;
     }
-    RNP_LOG("Unknown curve: %.*s", (int) bytes.size(), (char *) bytes.data());
+    RNP_LOG("Unknown curve: %.*s", (int) bytes.size(), (const char *) bytes.data());
     return false;
 }
 
@@ -806,7 +806,7 @@ g23_parse_seckey(pgp_key_pkt_t &seckey,
 
     auto &           alg_bt = alg_s_exp->sexp_string_at(0)->get_string();
     pgp_pubkey_alg_t alg = static_cast<pgp_pubkey_alg_t>(
-      id_str_pair::lookup(g10_alg_aliases, alg_bt.c_str(), PGP_PKA_NOTHING));
+      id_str_pair::lookup(g10_alg_aliases, (const char *) alg_bt.data(), PGP_PKA_NOTHING));
     if (alg == PGP_PKA_NOTHING) {
         RNP_LOG(
           "Unsupported algorithm: '%.*s'", (int) alg_bt.size(), (const char *) alg_bt.data());
--- comm/third_party/rnp/src/libsexpp/include/sexpp/sexp.h.orig	2024-10-25 23:29:32.000000000 +0000
+++ comm/third_party/rnp/src/libsexpp/include/sexpp/sexp.h	2024-10-27 06:14:59.238155000 +0000
@@ -44,8 +44,93 @@
 #include "sexp-public.h"
 #include "sexp-error.h"
 
+// We are implementing char traits for octet_t with trhe following restrictions
+//  -- limit visibility so that other traits for unsigned char are still possible
+//  -- create template specializatio in std workspace (use workspace specialization
+//     is not specified and causes issues at least with gcc 4.8
+
 namespace sexp {
+using octet_t = uint8_t;
+} // namespace sexp
 
+namespace std {
+
+template <> struct char_traits<sexp::octet_t> {
+    typedef sexp::octet_t  char_type;
+    typedef int            int_type;
+    typedef std::streampos pos_type;
+    typedef std::streamoff off_type;
+    typedef mbstate_t      state_type;
+
+    static void assign(char_type &__c1, const char_type &__c2) noexcept { __c1 = __c2; }
+
+    static constexpr bool eq(const char_type &__c1, const char_type &__c2) noexcept
+    {
+        return __c1 == __c2;
+    }
+
+    static constexpr bool lt(const char_type &__c1, const char_type &__c2) noexcept
+    {
+        return __c1 < __c2;
+    }
+
+    static int compare(const char_type *__s1, const char_type *__s2, size_t __n)
+    {
+        return memcmp(__s1, __s2, __n);
+    }
+
+    static size_t length(const char_type *__s)
+    {
+        return strlen(reinterpret_cast<const char *>(__s));
+    }
+
+    static const char_type *find(const char_type *__s, size_t __n, const char_type &__a)
+    {
+        return static_cast<const char_type *>(memchr(__s, __a, __n));
+    }
+
+    static char_type *move(char_type *__s1, const char_type *__s2, size_t __n)
+    {
+        return static_cast<char_type *>(memmove(__s1, __s2, __n));
+    }
+
+    static char_type *copy(char_type *__s1, const char_type *__s2, size_t __n)
+    {
+        return static_cast<char_type *>(memcpy(__s1, __s2, __n));
+    }
+
+    static char_type *assign(char_type *__s, size_t __n, char_type __a)
+    {
+        return static_cast<char_type *>(memset(__s, __a, __n));
+    }
+
+    static constexpr char_type to_char_type(const int_type &__c) noexcept
+    {
+        return static_cast<char_type>(__c);
+    }
+
+    // To keep both the byte 0xff and the eof symbol 0xffffffff
+    // from ending up as 0xffffffff.
+    static constexpr int_type to_int_type(const char_type &__c) noexcept
+    {
+        return static_cast<int_type>(static_cast<unsigned char>(__c));
+    }
+
+    static constexpr bool eq_int_type(const int_type &__c1, const int_type &__c2) noexcept
+    {
+        return __c1 == __c2;
+    }
+
+    static constexpr int_type eof() noexcept { return static_cast<int_type>(0xFFFFFFFF); }
+
+    static constexpr int_type not_eof(const int_type &__c) noexcept
+    {
+        return (__c == eof()) ? 0 : __c;
+    }
+};
+} // namespace std
+
+namespace sexp {
 /*
  * SEXP octet_t definitions
  * We maintain some presumable redundancy with ctype
@@ -99,14 +184,14 @@ class sexp_input_stream_t;
  * SEXP simple string
  */
 
-typedef uint8_t octet_t;
+using octet_traits = std::char_traits<octet_t>;
+using octet_string = std::basic_string<octet_t, octet_traits>;
 
-class SEXP_PUBLIC_SYMBOL sexp_simple_string_t : public std::basic_string<octet_t>,
-                                                private sexp_char_defs_t {
+class SEXP_PUBLIC_SYMBOL sexp_simple_string_t : public octet_string, private sexp_char_defs_t {
   public:
     sexp_simple_string_t(void) = default;
-    sexp_simple_string_t(const octet_t *dt) : std::basic_string<octet_t>{dt} {}
-    sexp_simple_string_t(const octet_t *bt, size_t ln) : std::basic_string<octet_t>{bt, ln} {}
+    sexp_simple_string_t(const octet_t *dt) : octet_string{dt} {}
+    sexp_simple_string_t(const octet_t *bt, size_t ln) : octet_string{bt, ln} {}
     sexp_simple_string_t &append(int c)
     {
         (*this) += (octet_t)(c & 0xFF);