crossdev: don't enable USE=pie by default on any bare-metal targets

Unfortunately embedded world has a long way to go
to adopt --enable-default-pie as a first class citizen.

Note:
  --enable-default-pie enabled two things:
    - PIC-friendly code generation (-fPIE)
    - PIE executables (-pie)

  Normally one would expect firmware to pass compiler modes explicitly
  to gcc: -fPIC (or -mauto-pic, -fno-PIC), -ffreestanding, -nostdlib.

  Unfortunately upstreams are frequently reluctant to explicitly specify
  new moving parts available in gcc (in this case -no-pie) and expect
  gcc to behave as it used to in the world before --enable-default-pie.
  Unfortunate but not entirely unreasonable.

Disable --enable-default-pie until user explicitly requests USE=pie.

Reported-by: Bertrand Jacquin
Reported-by: sklv
Bug: https://lists.gnupg.org/pipermail/gnuk-users/2018-August/000086.html
Bug: https://github.com/gl-sergei/u2f-token/issues/14
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>

1 files changed, 7 insertions, 6 deletions

diff --git a/crossdev b/crossdev
index 81bd50d..b8027a3 100755
--- a/crossdev
+++ b/crossdev
@@ -397,13 +397,14 @@ parse_target() {
 		# [2.] mingw32 startup code is broken: bug #644930
 		#      at least on i686-w64-mingw32 and x86_64-w64-mingw32
 		mingw*|*-mingw*) pie_support=no;;
-		# Some bare-metal targets don't work with pie as-is
+		# Many bare-metal targets don't work with pie as-is
 		*-elf|*-eabi)
-			case ${CTARGET} in
-				# mips can't generate freestanding PIC:
-				#   cc1: error: position-independent code requires ‘-mabicalls’
-				mips*) pie_support=no;;
-			esac
+			# mips can't generate freestanding PIC:
+			#   cc1: error: position-independent code requires ‘-mabicalls’
+			# arm firmware packages don't expect pie-by-default:
+			#   https://lists.gnupg.org/pipermail/gnuk-users/2018-August/000086.html
+			#   https://github.com/gl-sergei/u2f-token/issues/14
+			pie_support=no
 			;;
 	esac
 	if [[ $pie_support = "no" ]]; then