ext: isolate from container/std

These are too general to belong in the container package. This targets the v0.4 release to reduce the wrapper maintenance burden.

Signed-off-by: Ophestra <cat@gensokyo.uk>

ext/syscall_extra_linux_386.go

@@ -0,0 +1,13 @@
+package ext
+
+var syscallNumExtra = map[string]SyscallNum{
+	"kexec_file_load": SNR_KEXEC_FILE_LOAD,
+	"subpage_prot":    SNR_SUBPAGE_PROT,
+	"switch_endian":   SNR_SWITCH_ENDIAN,
+}
+
+const (
+	SNR_KEXEC_FILE_LOAD SyscallNum = __PNR_kexec_file_load
+	SNR_SUBPAGE_PROT    SyscallNum = __PNR_subpage_prot
+	SNR_SWITCH_ENDIAN   SyscallNum = __PNR_switch_endian
+)