Fix compiler error with 32 bit gcc 14 in Windows

[Biswa96]

This fixes the following compiler error.

../../gmime/gmime-gpgme-utils.c:69:9: error: initialization of
'gpgme_ssize_t (*)(void *, void *, size_t)' {aka 'long int (*)(void *, void *, unsigned int)'}
from incompatible pointer type
'ssize_t (*)(void *, void *, size_t)' {aka 'int (*)(void *, void *, unsigned int)'}
[-Wincompatible-pointer-types]
   69 |         g_mime_gpgme_stream_read,
      |         ^~~~~~~~~~~~~~~~~~~~~~~~

[Biswa96]

Click here to see full error output

``` ../../gmime/gmime-gpgme-utils.c:69:9: error: initialization of 'gpgme_ssize_t (*)(void *, void *, size_t)' {aka 'long int (*)(void *, void *, unsigned int)'} from incompatible pointer type 'ssize_t (*)(void *, void *, size_t)' {aka 'int (*)(void *, void *, unsigned int)'} [-Wincompatible-pointer-types] 69 | g_mime_gpgme_stream_read, | ^~~~~~~~~~~~~~~~~~~~~~~~ ../../gmime/gmime-gpgme-utils.c:69:9: note: (near initialization for 'gpg_stream_funcs.read') ../../gmime/gmime-gpgme-utils.c:70:9: error: initialization of 'gpgme_ssize_t (*)(void *, const void *, size_t)' {aka 'long int (*)(void *, const void *, unsigned int)'} from incompatible pointer type 'ssize_t (*)(void *, const void *, size_t)' {aka 'int (*)(void *, const void *, unsigned int)'} [-Wincompatible-pointer-types] 70 | g_mime_gpgme_stream_write, | ^~~~~~~~~~~~~~~~~~~~~~~~~ ../../gmime/gmime-gpgme-utils.c:70:9: note: (near initialization for 'gpg_stream_funcs.write') ../../gmime/gmime-gpgme-utils.c:71:9: error: initialization of 'gpgme_off_t (*)(void *, gpgme_off_t, int)' {aka 'long int (*)(void *, long int, int)'} from incompatible pointer type 'off_t (*)(void *, off_t, int)' {aka 'long long int (*)(void *, long long int, int)'} [-Wincompatible-pointer-types] 71 | g_mime_gpgme_stream_seek, | ^~~~~~~~~~~~~~~~~~~~~~~~ ../../gmime/gmime-gpgme-utils.c:71:9: note: (near initialization for 'gpg_stream_funcs.seek') ```