utils.c:utils_locale_to_utf8() specifies incorrect type for iconv_h

[paulsonx]

 191 /* Convert from system locale string to UTF-8 */
 192 int
 193 utils_locale_to_utf8(const char *src, size_t is, char *dest, size_t os)
 194 {
 195         static iconv_t *iconv_h = (iconv_t) - 1;
 196         if (strncmp(g_codepage, "UTF-8", strlen("UTF-8")) == 0)
 197                 goto pass_trough_as_is;
 198 
 199         if (g_iconv_works == False)
 200                 goto pass_trough_as_is;
 201 
 202         /* if not already initialize */
 203         if (iconv_h == (iconv_t) - 1)
 204         {
 205                 if ((iconv_h = iconv_open("UTF-8", g_codepage)) == (iconv_t     ) - 1)
 206                 {
 207                         logger(Core, Warning,
 208                                "utils_string_to_utf8(), iconv_open[%s -> %s     ] fail %p", g_codepage,
 209                                "UTF-8", iconv_h);
 210 
 211                         g_iconv_works = False;
 212                         goto pass_trough_as_is;
 213                 }
 214         }
 215 
 216         /* convert string */
 217         if (iconv(iconv_h, (char **) &src, &is, &dest, &os) == (size_t) - 1     )     

The iconv_h variable represents a 'conversion descriptor' as returned by iconv_open(3) which
the man page describes as:

       #include <iconv.h>

       iconv_t iconv_open(const char *tocode, const char *fromcode);

DESCRIPTION
       The   iconv_open()   function  returns  a  conversion  descriptor  that
       describes a conversion from the codeset specified by the string pointed
       to  by  the  fromcode  argument  to the codeset specified by the string
       pointed to by the tocode argument. For state-dependent  encodings,  the
[...]
RETURN VALUES
       Upon successful completion iconv_open() returns a conversion descriptor
       for use on subsequent calls to iconv(). Otherwise, iconv_open() returns
       (iconv_t)  -1 and sets errno to indicate the error.

The current implementation specifies iconv_h as a pointer to a conversion descriptor
which the compiler flags as being incorrect for all subsequent uses where a regular
conversion descriptor is expected:

checking iconv.h usability... yes
checking iconv.h presence... yes
checking for iconv.h... yes
checking for iconv... yes
checking for iconv declaration...
         extern size_t iconv (iconv_t cd, char * *inbuf, size_t *inbytesleft, char * *outbuf, size_t *outbytesleft);

gcc -g -O2 -Wall -Wextra -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS    -I/usr/include/idn -D_REENTRANT -I/usr/include/PCSC  -D_REENTRANT  -DPACKAGE_NAME=\"rdesktop\" -DPACKAGE_TARNAME=\"rdesktop\" -DPACKAGE_VERSION=\"1.9.0\" -DPACKAGE_STRING=\"rdesktop\ 1.9.0\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE_URL=\"\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -DL_ENDIAN=1 -DHAVE_SYS_SELECT_H=1 -DHAVE_SYS_FILIO_H=1 -DHAVE_LOCALE_H=1 -DHAVE_LANGINFO_H=1 -DHAVE_SYSEXITS_H=1 -DHAVE_XRANDR=1 -DHAVE_XCURSOR=1 -DWITH_SCARD=1 -DWITH_PNP_NOTIFICATIONS=1 -DEGD_SOCKET=\"/var/run/egd-pool\" -DWITH_RDPSND=1 -DRDPSND_OSS=1 -DRDPSND_SUN=1 -DRDPSND_PULSE=1 -DHAVE_DIRENT_H=1 -DHAVE_DIRFD=1 -DHAVE_DECL_DIRFD=1 -DHAVE_ICONV_H=1 -DHAVE_ICONV=1 -DICONV_CONST= -DHAVE_SYS_VFS_H=1 -DHAVE_SYS_STATVFS_H=1 -DHAVE_SYS_STATFS_H=1 -DHAVE_SYS_PARAM_H=1 -DHAVE_SYS_MOUNT_H=1 -DSTAT_STATVFS64=1 -DHAVE_STRUCT_STATVFS_F_NAMEMAX=1 -DKEYMAP_PATH=\"/usr/local/share/rdesktop/keymaps/\" -o utils.o -c utils.c
utils.c: In function ‘utils_locale_to_utf8’:
utils.c:195:28: warning: initialization of ‘struct _iconv_info **’ from incompatible pointer type ‘struct _iconv_info *’ [-Wincompatible-pointer-types]
  195 |  static iconv_t *iconv_h = (iconv_t) - 1;
      |                            ^
utils.c:203:14: warning: comparison of distinct pointer types lacks a cast
  203 |  if (iconv_h == (iconv_t) - 1)
      |              ^~
utils.c:205:16: warning: assignment to ‘struct _iconv_info **’ from incompatible pointer type ‘iconv_t’ {aka ‘struct _iconv_info *’} [-Wincompatible-pointer-types]
  205 |   if ((iconv_h = iconv_open("UTF-8", g_codepage)) == (iconv_t) - 1)
      |                ^
utils.c:205:51: warning: comparison of distinct pointer types lacks a cast
  205 |   if ((iconv_h = iconv_open("UTF-8", g_codepage)) == (iconv_t) - 1)
      |                                                   ^~
utils.c:217:12: warning: passing argument 1 of ‘iconv’ from incompatible pointer type [-Wincompatible-pointer-types]
  217 |  if (iconv(iconv_h, (char **) &src, &is, &dest, &os) == (size_t) - 1)
      |            ^~~~~~~
      |            |
      |            struct _iconv_info **
In file included from utils.c:24:
/usr/include/iconv.h:97:21: note: expected ‘iconv_t’ {aka ‘struct _iconv_info *’} but argument is of type ‘struct _iconv_info **’
   97 | extern size_t iconv(iconv_t, char **_RESTRICT_KYWD,
      |                     ^~~~~~~
utils.c:219:15: warning: passing argument 1 of ‘iconv_close’ from incompatible pointer type [-Wincompatible-pointer-types]
  219 |   iconv_close(iconv_h);
      |               ^~~~~~~
      |               |
      |               struct _iconv_info **
In file included from utils.c:24:
/usr/include/iconv.h:76:24: note: expected ‘iconv_t’ {aka ‘struct _iconv_info *’} but argument is of type ‘struct _iconv_info **’
   76 | extern int iconv_close(iconv_t);
      |                        ^~~~~~~
utils.c:220:11: warning: assignment to ‘struct _iconv_info **’ from incompatible pointer type ‘struct _iconv_info *’ [-Wincompatible-pointer-types]
  220 |   iconv_h = (iconv_t) - 1;
      |           ^

The following one line change fixes this issue and allows the compiler to build utils.c
without any warnings or errors:

--- utils.c.orig        2021-02-24 11:29:33.902415585 +0000
+++ utils.c     2021-02-24 11:29:35.257966901 +0000
@@ -192,7 +192,7 @@
 int
 utils_locale_to_utf8(const char *src, size_t is, char *dest, size_t os)
 {
-       static iconv_t *iconv_h = (iconv_t) - 1;
+       static iconv_t iconv_h = (iconv_t) - 1;
        if (strncmp(g_codepage, "UTF-8", strlen("UTF-8")) == 0)
                goto pass_trough_as_is;