LibC: Remove our iconv.h header and add libiconv port

If I ever end up writing my own iconv, i will drop the port :D

ports/libiconv/patches/0001-add-shared-library-support.patch

@@ -0,0 +1,31 @@
+diff -ruN libiconv-1.18/configure libiconv-1.18-banan_os/configure
+--- libiconv-1.18/configure	2024-12-15 13:57:14.000000000 +0200
++++ libiconv-1.18-banan_os/configure	2025-08-07 23:49:03.383717069 +0300
+@@ -8779,6 +8779,10 @@
+   lt_cv_deplibs_check_method=pass_all
+   ;;
+ 
++banan_os*)
++  lt_cv_deplibs_check_method=pass_all
++  ;;
++
+ beos*)
+   lt_cv_deplibs_check_method=pass_all
+   ;;
+@@ -14510,6 +14514,16 @@
+   esac
+   ;;
+ 
++banan_os*)
++  version_type=linux # correct to gnu/linux during the next big refactor
++  need_lib_prefix=no
++  need_version=no
++  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
++  soname_spec='$libname$release$shared_ext$major'
++  dynamic_linker="$host_os DynamicLoader.so"
++  shlibpath_var=LD_LIBRARY_PATH
++  ;;
++
+ beos*)
+   library_names_spec='$libname$shared_ext'
+   dynamic_linker="$host_os ld.so"

ports/libiconv/patches/0002-implement-getprogname.patch

@@ -0,0 +1,21 @@
+diff -ruN libiconv-1.18/srclib/getprogname.c libiconv-1.18-banan_os/srclib/getprogname.c
+--- libiconv-1.18/srclib/getprogname.c	2024-07-12 14:55:16.000000000 +0300
++++ libiconv-1.18-banan_os/srclib/getprogname.c	2025-08-07 23:42:50.691745454 +0300
+@@ -50,7 +50,7 @@
+ # include <sys/procfs.h>
+ #endif
+ 
+-#if defined __SCO_VERSION__ || defined __sysv5__
++#if defined __SCO_VERSION__ || defined __sysv5__ || defined __banan_os__
+ # include <fcntl.h>
+ # include <string.h>
+ #endif
+@@ -265,7 +265,7 @@
+         }
+     }
+   return NULL;
+-# elif defined __SCO_VERSION__ || defined __sysv5__                /* SCO OpenServer6/UnixWare */
++# elif defined __SCO_VERSION__ || defined __sysv5__ || defined __banan_os__                /* SCO OpenServer6/UnixWare */
+   char buf[80];
+   int fd;
+   sprintf (buf, "/proc/%d/cmdline", getpid());