procenv cannot handle utf-8 chars when producing XML or JSON output

$ src/procenv --locale
locale:
  LANG: fr_CA.UTF8
  LANGUAGE: fr_FR
  LC_ADDRESS: en_GB.UTF-8
  LC_COLLATE: fr_CA.UTF8
  LC_CTYPE: fr_FR.UTF-8
  LC_IDENTIFICATION: en_GB.UTF-8
  LC_MEASUREMENT: en_GB.UTF-8
  LC_MESSAGES: fr_CA.UTF8
  LC_MONETARY: en_GB.UTF-8
  LC_NAME: en_GB.UTF-8
  LC_NUMERIC: en_GB.UTF-8
  LC_PAPER: en_GB.UTF-8
  LC_TELEPHONE: en_GB.UTF-8
  LC_TIME: en_GB.UTF-8
  LC_ALL:
$ make check
           :
           :
INFO: Ensure /data/bzr/procenv/trunk/src/procenv runs with no errors
INFO: Ensure --file=<file> works
INFO: Ensure --output=stdout works
INFO: Ensure --output=stderr works
INFO: Ensure --exec works
INFO: Ensure '--format=text' works
INFO: Ensure '--format=crumb' works
INFO: Ensure '--format=xml' works
*** Error in `/data/bzr/procenv/trunk/src/procenv': malloc(): memory corruption: 0x0000000001235c20 ***
FAIL: check_all_args
======================================
1 of 3 tests failed
Please report to <email address hidden>
======================================
Makefile:476: recipe for target 'check-TESTS' failed
make[2]: *** [check-TESTS] Error 1
make[2]: Leaving directory '/data/bzr/procenv/trunk/src'
Makefile:599: recipe for target 'check-am' failed
make[1]: *** [check-am] Error 2
make[1]: Leaving directory '/data/bzr/procenv/trunk/src'
Makefile:427: recipe for target 'check-recursive' failed
make: *** [check-recursive] Error 1
$ gdb src/procenv ./src/core.24767
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License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
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and "show warranty" for details.
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Reading symbols from src/procenv...done.
[New LWP 24767]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `/data/bzr/procenv/trunk/src/procenv --format=xml'.
Program terminated with signal SIGABRT, Aborted.
#0 0x00007f70a3eb6f79 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
56 ../nptl/sysdeps/unix/sysv/linux/raise.c: Aucun fichier ou dossier de ce type.
(gdb) bt
#0 0x00007f70a3eb6f79 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#1 0x00007f70a3eba388 in __GI_abort () at abort.c:89
#2 0x00007f70a3ef41d4 in __libc_message (do_abort=1, fmt=fmt@entry=0x7f70a4002a10 "*** Error in `%s': %s: 0x%s ***\n") at ../sysdeps/posix/libc_fatal.c:175
#3 0x00007f70a3f01d76 in malloc_printerr (ptr=0x134bc20, str=0x7f70a3ffeb84 "malloc(): memory corruption", action=<optimized out>) at malloc.c:4996
#4 _int_malloc (av=0x7f70a423f760 <main_arena>, bytes=300) at malloc.c:3447
#5 0x00007f70a3f035f0 in __GI___libc_malloc (bytes=300) at malloc.c:2891
#6 0x00007f70a3efdbef in __GI__IO_str_overflow (fp=0x7fff5a684910, c=116) at strops.c:119
#7 0x00007f70a3efc54c in __GI__IO_default_xsputn (f=0x7fff5a684910, data=<optimized out>, n=8) at genops.c:480
#8 0x00007f70a3eca79a in _IO_vfprintf_internal (s=s@entry=0x7fff5a684910, format=<optimized out>, format@entry=0x4193a2 "<entry name=\"%s\">%s</entry>", ap=ap@entry=0x7fff5a684a48) at vfprintf.c:1692
#9 0x00007f70a3f8b385 in __GI___vasprintf_chk (result_ptr=result_ptr@entry=0x7fff5a684a40, flags=flags@entry=1, format=format@entry=0x4193a2 "<entry name=\"%s\">%s</entry>", args=args@entry=0x7fff5a684a48)
    at vasprintf_chk.c:66
#10 0x00000000004041e0 in vasprintf (__ap=0x7fff5a684a48, __fmt=<optimized out>, __ptr=0x7fff5a684a40) at /usr/include/x86_64-linux-gnu/bits/stdio2.h:210
#11 appendf (str=str@entry=0x624ab8 <doc>, fmt=fmt@entry=0x4193a2 "<entry name=\"%s\">%s</entry>") at procenv.c:2584
#12 0x00000000004078ab in entry (name=name@entry=0x41af24 "description", fmt=fmt@entry=0x4192b3 "'%s'") at procenv.c:1072
#13 0x0000000000417755 in show_signals () at procenv.c:1675
#14 0x0000000000418c0f in dump () at procenv.c:2956
#15 0x0000000000403587 in main (argc=2, argv=<optimized out>) at procenv.c:7143

Problem is that strerror(3) is returning utf-8 chars so procenv should convert all data to wchar_t.

Work around:

$ LANG=C make check