build: Don't build cloned_binary as part of crun

[darktohka]

Building crun after commit 8a0ee4b yields the following link error:

2024-11-28T01:45:15.2415817Z   CCLD     libcrun.la
2024-11-28T01:45:15.3802217Z   CCLD     crun
2024-11-28T01:45:15.4957602Z /home/runner/work/zebrafish/zebrafish/buildroot/output/host/lib/gcc/x86_64-buildroot-linux-gnu/13.3.0/../../../../x86_64-buildroot-linux-gnu/bin/ld: src/libcrun/crun-cloned_binary.o: in function `ensure_cloned_binary':
2024-11-28T01:45:15.4959563Z cloned_binary.c:(.text+0x87c): undefined reference to `get_bind_mount'
2024-11-28T01:45:15.4961482Z /home/runner/work/zebrafish/zebrafish/buildroot/output/host/lib/gcc/x86_64-buildroot-linux-gnu/13.3.0/../../../../x86_64-buildroot-linux-gnu/bin/ld: cloned_binary.c:(.text+0x8b7): undefined reference to `crun_error_release'
2024-11-28T01:45:15.4973731Z collect2: error: ld returned 1 exit status
2024-11-28T01:45:15.4989126Z make[3]: *** [Makefile:1547: crun] Error 1

This is because 8a0ee4b adds an include to "linux.h" (which has get_bind_mount and a transitive include to "error.h" which has crun_error_release). The Makefile for crun the binary builds src/libcrun/cloned_binary.c... which is already built as part of libcrun the library which is linked directly to crun.

Therefore it's enough to remove the src/libcrun/cloned_binary.c file from crun sources, it is already included through the link step.

An alternative would be to add src/libcrun/error.c, src/libcrun/utils.c, src/libcrun/linux.c to the crun sources, but that would be too much unnecessary bloat.