Fix -Werror=format-security compiler errors.
Patch for build failure

From https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=735755:

Hi there, . attached patch would fix this particular build failure, but I think
the package could need a general overhaul, given it has been 7 years since the
last upload ;). The example website (linuxfr.org) doesn't seem to be working
with this software anymore and I personally have no experience at all with it. .

Cheers, Andreas
Various autotools fixes.

In particular:
- Avoid recursive prefix (files were being installed in DESTDIR/DESTDIR/usr).
- Avoid "will not overwrite just-created" error caused by installing logo.xpm
  twice.
- Avoid "AC_RUN_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS" and
  "AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS" warnings.
- Avoid " 'INCLUDES' is the old name for 'AM_CPPFLAGS' (or '*_CPPFLAGS')"
  warning.
- Avoid "AC_CACHE_VAL(ac_have_backtrace, ...): suspicious cache-id, must
  contain _cv_ to be cached" . Avoid " The 'AM_PROG_MKDIR_P' macro is
  deprecated, and its use is discouraged."
Fix spelling-error-in-binary Lintian warnings.

Note that the remaining warnings are due to French spellings.
Fix -Wunused-variable compiler warnings.
Fix -Wunused-but-set-variable compiler warnings.
Fix -Wsizeof-pointer-memaccess compiler warning
Fix -Wunused-result compiler warnings.
Fix -Wtype-limits compiler warning.
Fix -Wimplicit-function-declaration compiler warnings.
Fix -Wpointer-to-int-cast compiler warning.
Fix -Wunused-but-set-parameter compiler warnings.
Fix -Wsign-compare compiler warnings.
Fix -Wmaybe-uninitialized compiler warnings.
Fix -Wparentheses compiler warnings.
Fix -Wint-to-pointer-cast compiler warnings.
Fix -Wunused-parameter compiler warnings.
Fix compiler warning.

In particular,
palmipede.c: In function ‘editw_insert_string’:
palmipede.c:572:3: warning: passing argument 2 of ‘convert_to_iso8859’
from incompatible pointer type [enabled by default]
   convert_to_iso8859("UTF-8", &s);
   ^
In file included from palmipede.c:193:0:
coin_util.h:94:6: note: expected ‘char **’ but argument is of type
‘unsigned char **’
 void convert_to_iso8859(const char *src_encoding, char **psrc);
      ^
inconsistent order of #include causes incompatible struct types

From https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=702439:

While building the package using our research compiler infrastructure we noticed
incompatible types of struct re_pattern_buffer (from regex.h) being used within
the declaration of GeneralPrefs Prefs.

The root cause of this problem is that src/cc_queue.c includes system headers
*before* local header files, thus _GNU_SOURCE will not be set when processing
regex.h. In src/board.c, however, local header files are processed first,
resulting in different expansions of global.h.

Best, Michael
Merge pull request #1 from d-torrance/debian-patches

Debian patches