seq66: fix build against gcc-13

Without the chnage build fails on `master` as:

    In file included from os/daemonize.cpp:64:
    ../include/os/daemonize.hpp:58:8: error: 'uint32_t' does not name a type
       58 | extern uint32_t daemonize
          |        ^~~~~~~~
    ../include/os/daemonize.hpp:36:1: note: 'uint32_t' is defined in header '<cstdint>'; did you forget to '#include <cstdint>'?
       35 | #include "seq66_platform_macros.h"      /* for detecting 32-bit builds      */
      +++ |+#include <cstdint>

As upstream changes are quite invasive for backport I am only injecting
missing headers.

pkgs/applications/audio/seq66/default.nix

@@ -21,6 +21,10 @@ stdenv.mkDerivation rec {
     for d in libseq66/include libseq66/src libsessions/include libsessions/src seq_qt5/src seq_rtmidi/include seq_rtmidi/src Seqtool/src; do
       substituteInPlace "$d/Makefile.am" --replace '$(git_info)' '${version}'
     done
+
+    # gcc-13 headers compatibilty. TODO: try to remove with next version
+    # update
+    sed -e '1i #include <cstdint>' -i libseq66/src/os/daemonize.cpp
   '';
 
   enableParallelBuilding = true;