[dev.boringcrypto] crypto/internal/boring: clear "executable stack" bit from syso

Change-Id: Ie9dd13f3ae78a423a231f47e746a38f96768b93c
Reviewed-on: https://go-review.googlesource.com/58830
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/crypto/internal/boring/build/build.sh

@@ -57,7 +57,7 @@ mkdir $chroot/godriver
 cp ../goboringcrypto.h $chroot/godriver
 
 sudo http_proxy=$http_proxy chroot $chroot /root_setup_in_chroot.sh
-sudo chroot --userspec=$USER:$USER $chroot /build_in_chroot.sh
+sudo chroot --userspec=$(id -u):$(id -g) $chroot /build_in_chroot.sh
 cp $chroot/godriver/goboringcrypto_linux_amd64.syso ..
 sha256sum ../goboringcrypto_linux_amd64.syso
 echo DONE

src/crypto/internal/boring/build/build_in_chroot.sh

@@ -183,6 +183,8 @@ __umodti3:
 	xorl %ecx, %ecx
 	movl %ecx, 0(%ecx)
 	jmp 1b
+
+.section .note.GNU-stack,"",@progbits
 EOF
 clang-4.0 -c -o umod.o umod.s