[Bug] does not compile with GCC 15

[neheb]

Describe the bug
GCC 15 cannot compile as it defaults to C23 now.

To Reproduce
Steps to reproduce the behavior:

1. Compile with GCC 15.

Expected behavior
Compilation succeeding

Additional context

bget.c:565:1: warning: old-style function definition [-Wold-style-definition]
  565 | bget(requested_size)
      | ^~~~
bget.c:567:1: error: number of arguments doesn't match prototype
  567 | {
      | ^

probably more than this.