main/gcc: fix build with musl 1.2.3

fix the build error:
sysinfo.go:6606:7: error: redefinition of 'SYS_SECCOMP'
 6606 | const SYS_SECCOMP = _SYS_SECCOMP
      |       ^
sysinfo.go:6600:7: note: previous definition of 'SYS_SECCOMP' was here
 6600 | const SYS_SECCOMP = _SYS_seccomp
      |       ^

Upstream report:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105225