[gmime] Drop the use of ICONV_CONST

[Jeffrey Stedfast <fejj src gnome org>]

commit e76a8002ebbe2324b1ba678f038c565ae7f63e58
Author: Jeffrey Stedfast <fejj gnome org>
Date:   Fri Dec 9 20:05:03 2016 -0500

    Drop the use of ICONV_CONST

 configure.ac                 |    4 +---
 gmime/gmime-filter-charset.c |    4 ++--
 2 files changed, 3 insertions(+), 5 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index aac3fe2..894ee67 100644
--- a/configure.ac
+++ b/configure.ac
@@ -306,13 +306,11 @@ AS_IF([test x"$glib_native_win32" != xyes], [
 AC_SUBST(ICONV_LIBS)
 
 case $with_libiconv in
-  gnu|no)
+  gnu)
     AC_DEFINE(USE_LIBICONV_GNU, 1, [Using GNU libiconv])
-    AC_DEFINE(ICONV_CONST, [const], [GNU libiconv uses const char**])
     ;;
   native)
     AC_DEFINE(USE_LIBICONV_NATIVE, 1, [Using a native implementation of iconv in a separate library])
-    AC_DEFINE(ICONV_CONST, [], [GNU libiconv uses const char**])
     ;;
 esac
 
diff --git a/gmime/gmime-filter-charset.c b/gmime/gmime-filter-charset.c
index c3f3d18..052268e 100644
--- a/gmime/gmime-filter-charset.c
+++ b/gmime/gmime-filter-charset.c
@@ -147,7 +147,7 @@ filter_filter (GMimeFilter *filter, char *in, size_t len, size_t prespace,
        inleft = len;
        
        do {
-               converted = iconv (charset->cd, (ICONV_CONST char **) &inbuf, &inleft, (ICONV_CONST char **) 
&outbuf, &outleft);
+               converted = iconv (charset->cd, &inbuf, &inleft, &outbuf, &outleft);
                if (converted == (size_t) -1) {
                        if (errno == E2BIG || errno == EINVAL)
                                break;
@@ -215,7 +215,7 @@ filter_complete (GMimeFilter *filter, char *in, size_t len, size_t prespace,
        
        if (inleft > 0) {
                do {
-                       converted = iconv (charset->cd, (ICONV_CONST char **) &inbuf, &inleft, (ICONV_CONST 
char **) &outbuf, &outleft);
+                       converted = iconv (charset->cd, &inbuf, &inleft, &outbuf, &outleft);
                        if (converted != (size_t) -1)
                                continue;