Add sys_exec () and libprocess wrapper, fix ramdisk tar parsing

kernel/libk/string.c

@@ -44,3 +44,16 @@ int memcmp (const void* s1, const void* s2, size_t n) {
   }
   return 0;
 }
+
+int strncmp (const char* s1, const char* s2, size_t n) {
+  while (n && *s1 && (*s1 == *s2)) {
+    ++s1;
+    ++s2;
+    --n;
+  }
+  if (n == 0) {
+    return 0;
+  } else {
+    return (*(unsigned char*)s1 - *(unsigned char*)s2);
+  }
+}