Gcc16 ext2fs

[mitchellwaite]

These changes make the ext2fs library compile properly against GCC16, and should also be compatible with GCC 9.2.0 until such a time as libxenon is updated.

• Implicit function definitions are errors by default in the new GCC, this trips up mkjournal:

mkjournal.c:64:33: error: implicit declaration of function 'htonl' [-Wimplicit-function-declaration]
   64 |         jsb->s_header.h_magic = htonl(JFS_MAGIC_NUMBER);
      |                                 ^~~~~

• default C standard in GCC16 doesn't allow "typedef int bool;", so the makefile enables the GNU11 standard that was default with the older compiler

/mnt/d/Documents/GitHub/libext2fs/source/tdb.c:107:13: error: 'bool' cannot be defined via 'typedef'
  107 | typedef int bool;
      |             ^~~~
/mnt/d/Documents/GitHub/libext2fs/source/tdb.c:107:13: note: 'bool' is a keyword with '-std=c23' onwards