unistr use of undefined macros

[Ludovic Courtès]

Hello,

Commit c98cb289 changed #ifdefs in unistr.in.h to #ifs.  As a
side-effect, this prevents compilation of users of this file, such as
Guile, with ‘-Wundef’:

--8<---------------cut here---------------start------------->8---
In file included from bytevectors.c:43:0:
../lib/unistr.h:161:5: error: "GNULIB_UNISTR_U16_MBTOUC_UNSAFE" is not defined
../lib/unistr.h:184:5: error: "GNULIB_UNISTR_U32_MBTOUC_UNSAFE" is not defined
../lib/unistr.h: In function 'u32_mbtouc_unsafe':
../lib/unistr.h:195:7: error: "CONFIG_UNICODE_SAFETY" is not defined
../lib/unistr.h:199:7: error: "CONFIG_UNICODE_SAFETY" is not defined
../lib/unistr.h: At top level:
../lib/unistr.h:232:5: error: "GNULIB_UNISTR_U16_MBTOUC" is not defined
../lib/unistr.h:255:5: error: "GNULIB_UNISTR_U32_MBTOUC" is not defined
../lib/unistr.h:288:5: error: "GNULIB_UNISTR_U16_MBTOUCR" is not defined
../lib/unistr.h:293:5: error: "GNULIB_UNISTR_U32_MBTOUCR" is not defined
../lib/unistr.h:326:5: error: "GNULIB_UNISTR_U16_UCTOMB" is not defined
../lib/unistr.h:348:5: error: "GNULIB_UNISTR_U32_UCTOMB" is not defined
make[1]: *** [libguile_2.0_la-bytevectors.lo] Error 1
--8<---------------cut here---------------end--------------->8---

In addition, a quick grep through Gnulib suggests that there’s no way
for these macros to be defined:

--8<---------------cut here---------------start------------->8---
$ grep -E '(CONFIG_UNICODE_SAFETY|GNULIB_UNISTR_U[0-9][0-9]_(MBTOUC|UCTOMB))' 
~/src/gnulib/*/*
/home/ludo/src/gnulib/lib/unistr.in.h:#if GNULIB_UNISTR_U16_MBTOUC_UNSAFE || 
HAVE_LIBUNISTRING
/home/ludo/src/gnulib/lib/unistr.in.h:#if GNULIB_UNISTR_U32_MBTOUC_UNSAFE || 
HAVE_LIBUNISTRING
/home/ludo/src/gnulib/lib/unistr.in.h:#  if CONFIG_UNICODE_SAFETY
/home/ludo/src/gnulib/lib/unistr.in.h:#  if CONFIG_UNICODE_SAFETY
/home/ludo/src/gnulib/lib/unistr.in.h:#if GNULIB_UNISTR_U16_MBTOUC || 
HAVE_LIBUNISTRING
/home/ludo/src/gnulib/lib/unistr.in.h:#if GNULIB_UNISTR_U32_MBTOUC || 
HAVE_LIBUNISTRING
/home/ludo/src/gnulib/lib/unistr.in.h:#if GNULIB_UNISTR_U16_MBTOUCR || 
HAVE_LIBUNISTRING
/home/ludo/src/gnulib/lib/unistr.in.h:#if GNULIB_UNISTR_U32_MBTOUCR || 
HAVE_LIBUNISTRING
/home/ludo/src/gnulib/lib/unistr.in.h:#if GNULIB_UNISTR_U16_UCTOMB || 
HAVE_LIBUNISTRING
/home/ludo/src/gnulib/lib/unistr.in.h:#if GNULIB_UNISTR_U32_UCTOMB || 
HAVE_LIBUNISTRING
--8<---------------cut here---------------end--------------->8---

Is it an omission, or am I missing something?

Thanks,
Ludo’.