dpkg-buildflags: Do not blacklist pie and stackprotector on mips/mipsel

pie is blacklisted on mips and mipsel, according to the comments due
to #526961. This bug has been fixed more than 4 years ago, it's time
to reactivate pie support.

Similarly strack-protector support has been added on mips and mipsel
in gcc 4.6 so we can now activate it too.

Closes: #763672

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Guillem Jover <guillem@debian.org>

debian/changelog

@@ -1,6 +1,7 @@
 dpkg (1.17.15) UNRELEASED; urgency=low
 
-  *
+  * Do not blacklist pie and stackprotector build flags on mips/mipsel.
+    Thanks to Aurelien Jarno <aurelien@aurel32.net>. Closes: #763672
 
  -- Guillem Jover <guillem@debian.org>  Mon, 06 Oct 2014 02:43:41 +0200
 

scripts/Dpkg/Vendor/Debian.pm

@@ -194,14 +194,14 @@ sub _add_hardening_flags {
 
     # Mask features that are not available on certain architectures.
     if ($os !~ /^(?:linux|knetbsd|hurd)$/ or
-	$cpu =~ /^(?:hppa|mips|mipsel|avr32)$/) {
+	$cpu =~ /^(?:hppa|avr32)$/) {
 	# Disabled on non-linux/knetbsd/hurd (see #430455 and #586215).
-	# Disabled on hppa, mips/mipsel (#532821), avr32
+	# Disabled on hppa, avr32
 	#  (#574716).
 	$use_feature{pie} = 0;
     }
-    if ($cpu =~ /^(?:ia64|alpha|mips|mipsel|hppa)$/ or $arch eq 'arm') {
-	# Stack protector disabled on ia64, alpha, mips, mipsel, hppa.
+    if ($cpu =~ /^(?:ia64|alpha|hppa)$/ or $arch eq 'arm') {
+	# Stack protector disabled on ia64, alpha, hppa.
 	#   "warning: -fstack-protector not supported for this target"
 	# Stack protector disabled on arm (ok on armel).
 	#   compiler supports it incorrectly (leads to SEGV)