scsh: fix build with gcc15 (#516296)

pkgs/by-name/sc/scsh/gcc-15.patch

@@ -0,0 +1,13 @@
+diff --git a/c/syscalls.c b/c/syscalls.c
+index 2be25a8..311f02b 100644
+--- a/c/syscalls.c
++++ b/c/syscalls.c
+@@ -670,7 +670,7 @@ s48_ref_t scm_gethostname(s48_call_t call)
+ {
+    char hostname[MAXHOSTNAMELEN+1];
+     /* different OS's declare differently, so punt the prototype. */
+-    int gethostname();
++    int gethostname(char *name, size_t size);
+     int retval = gethostname(hostname, MAXHOSTNAMELEN);
+     if (retval == -1) s48_os_error_2(call, "scm_gethostname", errno, 0);
+     return s48_enter_byte_string_2(call, hostname);

pkgs/by-name/sc/scsh/package.nix

@@ -26,6 +26,9 @@ stdenv.mkDerivation {
     # Fix the build against gcc-14:
     # https://github.com/scheme/scsh/pull/51
     ./gcc-14-p2.patch
+    # Fix the build against gcc-15:
+    # https://github.com/scheme/scsh/pull/52
+    ./gcc-15.patch
   ];
 
   nativeBuildInputs = [ autoreconfHook ];