style(string): satisfy clang-tidy and clang-format for final-wave gate

Suppress clang-analyzer-security buffer-handling diagnostics on the
plan-mandated __builtin_memcpy word loads and bugprone swappable-
parameter diagnostics on the C-standard signatures; wrap the autoconf
substitution tokens in clang-format off/on (the space clang-format wants
before the closing @ would break config.status substitution).

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <[email protected]>

src/string/memcpy.c

@@ -16,9 +16,8 @@
  * self-recursion and stack overflow. Disable that one transformation for
  * this function only.
  */
-__attribute__((optimize("no-tree-loop-distribute-patterns")))
-void *
-memcpy(void *restrict dst, const void *restrict src, size_t n)
+__attribute__((optimize("no-tree-loop-distribute-patterns"))) void *
+memcpy(void *restrict dst, const void *restrict src, size_t n) // NOLINT(bugprone-*)
 {
     const unsigned long word = sizeof(unsigned long);
     unsigned char *d = dst;
@@ -35,8 +34,8 @@ memcpy(void *restrict dst, const void *restrict src, size_t n)
     {
         unsigned long w;
 
-        __builtin_memcpy(&w, s, sizeof w);
-        __builtin_memcpy(d, &w, sizeof w);
+        __builtin_memcpy(&w, s, sizeof w); // NOLINT(clang-analyzer-security.insecureAPI.*)
+        __builtin_memcpy(d, &w, sizeof w); // NOLINT(clang-analyzer-security.insecureAPI.*)
         d += word;
         s += word;
         n -= word;