Peter Mazinger asked for this several months ago.

include/elf.h

@@ -565,6 +565,8 @@ typedef struct
 #define	PT_NUM		8		/* Number of defined types */
 #define PT_LOOS		0x60000000	/* Start of OS-specific */
 #define PT_GNU_EH_FRAME	0x6474e550	/* GCC .eh_frame_hdr segment */
+#define PT_GNU_STACK	0x6474e551	/* Indicates stack executability */
+#define PT_GNU_RELRO	0x6474e552	/* Read-only after relocation */
 #define PT_LOSUNW	0x6ffffffa
 #define PT_SUNWBSS	0x6ffffffa	/* Sun Specific segment */
 #define PT_SUNWSTACK	0x6ffffffb	/* Stack segment */