Tweaks before tackling the new ROP chains

- Added read8/read16/write8/write16 functions
- Simplify shellcode a little bit more
- Didn't init chain before using it for setuid check

src/kpatch/types.h

@@ -15,7 +15,8 @@ GNU Affero General Public License for more details.
 You should have received a copy of the GNU Affero General Public License
 along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
 
-#pragma once
+#ifndef TYPES_H_
+#define TYPES_H_
 
 typedef unsigned char u8;
 typedef unsigned short u16;
@@ -26,3 +27,5 @@ typedef signed char s8;
 typedef signed short s16;
 typedef signed int s32;
 typedef signed long long s64;
+
+#endif