sys/targets: disable some GCC warnings reported for C reproducers

Disable GCC warnings:
* stringop-overflow
* array-bounds
* format-overflow

These warnings generate false positives for C reproducers which cause
GCC to fail if -Werror is given.

This commit fixes the following false positives:

/root/test.c: In function ‘main’:
/root/test.c:88:50: error: writing 1 byte into a region of size 0 [-Werror=stringop-overflow=]
88 | NONFAILING(*(uint8_t*)0x20000088 = 3);

/root/test.c:85:28: error: ‘memcpy’ offset [0, 23] is out of the bounds [0, 0] [-Werror=array-bounds]
85 | NONFAILING(memcpy((void*)0x20000040, "\001\000\000\000\002\000\000\000\003\000\004\000\000\000\000\000\005\000\000\000\000\000\000\000", 24));

<stdin>:86:40: error: ‘%023llo’ directive writing 23 bytes into a region of size 0 [-Werror=format-overflow=]
<stdin>:43:123: note: in definition of macro ‘NONFAILING’

GCC stringop-overflow bug reports:
- https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88443

syzkaller group discussion:
- https://groups.google.com/g/syzkaller/c/PIEYPflPWhQ

0 files changed, 0 insertions, 0 deletions