Compile RTLD with global dot symbols on 64-bit PowerPC, as a crutch for

GDB's ability to locate r_debug_state (which is actually the only function
that need be compiled this way).

libexec/rtld-elf/Makefile

@@ -17,6 +17,7 @@ RTLD_ARCH=	${MACHINE_CPUARCH}
 .endif
 CFLAGS+=	-I${.CURDIR}/${RTLD_ARCH} -I${.CURDIR}
 .if ${MACHINE_ARCH} == "powerpc64"
+CFLAGS+=	-mcall-aixdesc
 LDFLAGS+=	-nostdlib -e _rtld_start
 .else
 LDFLAGS+=	-nostdlib -e .rtld_start