Bug#841474: afl: FTBFS on armhf (illegal instruction on test-instr.c)

[Daniel Stender]

Package: afl
Version: 2.34b-2
Severity: serious
Justification: fails to build from source (but built successfully in the past)

>From 2.30b-1 onwards (the first package which was tried to build against llvm-toolchain
> 3.7 on this arch), AFL build breaks with "illegal instruction" trying to compile
test-instr.c with afl-clang-fast, now trying to build with clang 3.9 [1]:

<cut>
[*] Testing the CC wrapper and instrumentation output...
unset AFL_USE_ASAN AFL_USE_MSAN AFL_INST_RATIO; AFL_QUIET=1 AFL_PATH=. AFL_CC=clang-3.9
../afl-clang-fast -g -O2 -fdebug-prefix-map=/«PKGBUILDDIR»=. -fPIE -fstack-protector-strong
-Wformat -Werror=format-security -Wall -D_FORTIFY_SOURCE=2 -g -Wno-pointer-sign
-DAFL_PATH=\"/usr/lib/afl\" -DBIN_PATH=\"/usr/bin\" -DVERSION=\"2.34b\"  ../test-instr.c -o
test-instr -fPIE -pie -Wl,-z,relro -Wl,-z,now
Illegal instruction
</cut>

Julien Puydt has reported something similar for the flint package:
https://bugs.debian.org/798111 (Illegal instruction after compiling some code)

Strangely, the package builds fine in the porterbox and with a qemu-bootstrapped local
sbuild [2].

Thanks for any input (if this could be worked around in the AFL package),
I'll try to seek what's causing this in the build toolchain.
DS

[1] https://buildd.debian.org/status/fetch.php?pkg=afl&arch=armhf&ver=2.34b-2&stamp=1474836143

[2] http://www.danielstender.com/buildlogs/afl_2.34b-2_armhf-2016-10-20T23:40:16Z.build

-- System Information:
Debian Release: stretch/sid
  APT prefers testing
  APT policy: (500, 'testing'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 4.7.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=de_DE.utf8, LC_CTYPE=de_DE.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages afl depends on:
ii  build-essential  12.2
ii  libc6            2.24-3

Versions of packages afl recommends:
pn  afl-clang  <none>
ii  afl-doc    2.34b-2

Versions of packages afl suggests:
ii  gnuplot  5.0.4+dfsg1-3

-- no debconf information