diff -ru source/mg.c source-new/mg.c
--- source/mg.c	2017-06-30 14:03:22.000000000 -0700
+++ source-new/mg.c	2017-08-17 14:40:37.669507085 -0700
@@ -3034,16 +3034,16 @@
 #ifdef HAS_SETRESUID
         PERL_UNUSED_RESULT(setresuid(new_uid, (Uid_t)-1, (Uid_t)-1));
 #else
-	if (new_uid == PerlProc_geteuid()) {		/* special case $< = $> */
+//	if (new_uid == PerlProc_geteuid()) {		/* special case $< = $> */
 #ifdef PERL_DARWIN
 	    /* workaround for Darwin's setuid peculiarity, cf [perl #24122] */
 	    if (new_uid != 0 && PerlProc_getuid() == 0)
                 PERL_UNUSED_RESULT(PerlProc_setuid(0));
 #endif
-            PERL_UNUSED_RESULT(PerlProc_setuid(new_uid));
-	} else {
+//            PERL_UNUSED_RESULT(PerlProc_setuid(new_uid));
+//	} else {
 	    Perl_croak(aTHX_ "setruid() not implemented");
-	}
+//	}
 #endif
 #endif
 #endif
@@ -3067,11 +3067,11 @@
 #ifdef HAS_SETRESUID
 	PERL_UNUSED_RESULT(setresuid((Uid_t)-1, new_euid, (Uid_t)-1));
 #else
-	if (new_euid == PerlProc_getuid())		/* special case $> = $< */
-	    PERL_UNUSED_RESULT(PerlProc_setuid(new_euid));
-	else {
+//	if (new_euid == PerlProc_getuid())		/* special case $> = $< */
+//	    PERL_UNUSED_RESULT(PerlProc_setuid(new_euid));
+//	else {
 	    Perl_croak(aTHX_ "seteuid() not implemented");
-	}
+//	}
 #endif
 #endif
 #endif
@@ -3095,11 +3095,11 @@
 #ifdef HAS_SETRESGID
         PERL_UNUSED_RESULT(setresgid(new_gid, (Gid_t)-1, (Gid_t) -1));
 #else
-	if (new_gid == PerlProc_getegid())			/* special case $( = $) */
-	    PERL_UNUSED_RESULT(PerlProc_setgid(new_gid));
-	else {
+//	if (new_gid == PerlProc_getegid())			/* special case $( = $) */
+//	    PERL_UNUSED_RESULT(PerlProc_setgid(new_gid));
+//	else {
 	    Perl_croak(aTHX_ "setrgid() not implemented");
-	}
+//	}
 #endif
 #endif
 #endif
@@ -3178,11 +3178,11 @@
 #ifdef HAS_SETRESGID
 	PERL_UNUSED_RESULT(setresgid((Gid_t)-1, new_egid, (Gid_t)-1));
 #else
-	if (new_egid == PerlProc_getgid())			/* special case $) = $( */
-	    PERL_UNUSED_RESULT(PerlProc_setgid(new_egid));
-	else {
+//	if (new_egid == PerlProc_getgid())			/* special case $) = $( */
+//	    PERL_UNUSED_RESULT(PerlProc_setgid(new_egid));
+//	else {
 	    Perl_croak(aTHX_ "setegid() not implemented");
-	}
+//	}
 #endif
 #endif
 #endif
diff -ru source/perl.h source-new/perl.h
--- source/perl.h	2017-06-30 14:03:22.000000000 -0700
+++ source-new/perl.h	2017-08-17 13:14:01.806883580 -0700
@@ -1061,7 +1061,6 @@
 #ifndef PERL_MICRO
 #ifndef memchr
 #   ifndef HAS_MEMCHR
-#       define memchr(s,c,n) ninstr((char*)(s), ((char*)(s)) + n, &(c), &(c) + 1)
 #   endif
 #endif
 #endif
diff -ru source/pp_hot.c source-new/pp_hot.c
--- source/pp_hot.c	2017-06-30 14:03:22.000000000 -0700
+++ source-new/pp_hot.c	2017-08-17 13:16:20.234635700 -0700
@@ -1583,11 +1583,13 @@
 		PL_delaymagic &= ~DM_EUID;
 	    }
 #    endif /* HAS_SETEUID */
+#if 0
 	    if (PL_delaymagic & DM_UID) {
 		if (PL_delaymagic_uid != PL_delaymagic_euid)
 		    DIE(aTHX_ "No setreuid available");
 		PERL_UNUSED_RESULT(PerlProc_setuid(PL_delaymagic_uid));
 	    }
+#endif
 #  endif /* HAS_SETREUID */
 #endif /* HAS_SETRESUID */
 
@@ -1619,11 +1621,13 @@
 		PL_delaymagic &= ~DM_EGID;
 	    }
 #    endif /* HAS_SETEGID */
+#if 0
 	    if (PL_delaymagic & DM_GID) {
 		if (PL_delaymagic_gid != PL_delaymagic_egid)
 		    DIE(aTHX_ "No setregid available");
 		PERL_UNUSED_RESULT(PerlProc_setgid(PL_delaymagic_gid));
 	    }
+#endif
 #  endif /* HAS_SETREGID */
 #endif /* HAS_SETRESGID */
 
diff -ru source/pp_sys.c source-new/pp_sys.c
--- source/pp_sys.c	2017-06-30 14:03:22.000000000 -0700
+++ source-new/pp_sys.c	2017-08-17 14:57:00.983541027 -0700
@@ -2413,7 +2413,7 @@
     TAINT_PROPER(PL_op_desc[optype]);
 
     if (optype == OP_IOCTL)
-#ifdef HAS_IOCTL
+#if 0
 	retval = PerlLIO_ioctl(PerlIO_fileno(IoIFP(io)), func, s);
 #else
 	DIE(aTHX_ "ioctl is not implemented");
@@ -2705,7 +2705,7 @@
     if (!IoIFP(io))
 	goto nuts;
 
-    PUSHi( PerlSock_shutdown(PerlIO_fileno(IoIFP(io)), how) >= 0 );
+    PUSHi( 0 );
     RETURN;
 
   nuts:
@@ -2980,7 +2980,7 @@
         sv_setuid(PUSHmortal, PL_statcache.st_uid);
         sv_setgid(PUSHmortal, PL_statcache.st_gid);
 
-#ifdef USE_STAT_RDEV
+#if 0
 	mPUSHi(PL_statcache.st_rdev);
 #else
 	PUSHs(newSVpvs_flags("", SVs_TEMP));
@@ -4186,7 +4186,7 @@
 
 PP(pp_fork)
 {
-#ifdef HAS_FORK
+#if 1
     dSP; dTARGET;
     Pid_t childpid;
 #ifdef HAS_SIGPROCMASK
@@ -4332,7 +4332,7 @@
 	TAINT_PROPER("system");
     }
     PERL_FLUSHALL_FOR_CHILD;
-#if (defined(HAS_FORK) || defined(__amigaos4__)) && !defined(VMS) && !defined(OS2) || defined(PERL_MICRO)
+#if 1
     {
 #ifdef __amigaos4__
         struct UserData userdata;
@@ -5582,7 +5582,7 @@
 
 PP(pp_ggrent)
 {
-#ifdef HAS_GROUP
+#if 0
     dSP;
     const I32 which = PL_op->op_type;
     const struct group *grent;
diff -ru source/util.c source-new/util.c
--- source/util.c	2017-06-30 14:03:22.000000000 -0700
+++ source-new/util.c	2017-08-17 14:47:03.963804576 -0700
@@ -2842,7 +2842,7 @@
 #endif /* HAS_FORK */
 }
 
-#ifndef HAS_DUP2
+#if 0
 int
 dup2(int oldfd, int newfd)
 {