charset: rename IBM866 to CP866 for iconv and adjust charset names for codeset

```
linux $ iconv -l | grep 866
866//
866NAV//
CP866//
CP866NAV//
CSIBM866//
IBM866//
IBM866NAV//

solaris $ iconv -l | grep 866
    CP866 (CP866, CP-866, CP_866, 866),
    IBM-866,

macos % iconv -l | grep 866
CP866 866 CSIBM866 IBM866 MSCP866

musl/src/locale/codepages.h: "cp866\0"
```

On glibc-based systems, codeset will be set to charmap name, on most other systems it seems to be taken from locale name.

## Linux

```
zaytsev@fedora:~$ locale -a | grep ru
ru_RU
ru_RU.cp866
ru_RU.ibm866
ru_RU.iso88595
ru_RU.koi8r
ru_RU.utf8
russian
ru_UA
ru_UA.koi8u
ru_UA.utf8

zaytsev@fedora:~/src$ LC_ALL=ru_RU.cp866 LANG=ru_RU.cp866 ./a.out
IBM866

zaytsev@fedora:~/src$ LC_ALL=ru_RU.koi8r LANG=ru_RU.koi8r ./a.out
KOI8-R

zaytsev@fedora:~/src$ LC_ALL=ru_RU.iso88595 LANG=ru_RU.iso88595 ./a.out
ISO-8859-5
```

## macOS

```
ru_RU.ISO8859-5
ru_RU.CP866
ru_RU.CP1251
ru_RU.UTF-8
ru_RU.KOI8-R
ru_RU

zaytsev@Yurys-MBP mc % LANG=ru_RU.CP866 LC_ALL=ru_RU.CP866 ./a.out
CP866

zaytsev@Yurys-MBP mc % LANG=ru_RU.ISO8859-5 LC_ALL=ru_RU.ISO8859-5 ./a.out
ISO8859-5
```

## FreeBSD

```
ru_RU.CP1251
ru_RU.CP866
ru_RU.ISO8859-5
ru_RU.KOI8-R
ru_RU.UTF-8

zaytsev@cfarm240:~ $ LANG=ru_RU.ISO8859-5 LC_ALL=ru_RU.ISO8859-5 ./a.out
ISO8859-5

zaytsev@cfarm240:~ $ LANG=ru_RU.CP866 LC_ALL=ru_RU.CP866 ./a.out
CP866
```

## Solaris

```
ru
ru.UTF-8
ru.koi8-r
ru_RU
ru_RU.ANSI1251
ru_RU.ISO8859-5
ru_RU.KOI8-R
ru_RU.UTF-8

zaytsev@gcc-solaris10:~/src$ LANG=ru_RU.ISO8859-5 LC_ALL=ru_RU.ISO8859-5 ./a.o>
ISO8859-5

zaytsev@gcc-solaris10:~/src$ LANG=ru.koi8-r LC_ALL=ru.koi8-r ./a.out
KOI8-R
```

## AIX

```
zaytsev@gcc111:[/home/zaytsev]locale -a
C
POSIX
en_US.8859-15
en_US.IBM-858
en_US.ISO8859-1
en_US

-bash-5.1$ LANG=en_US.ISO8859-1 LC_ALL=en_US.ISO8859-1 ./a.out
ISO8859-1
```

Signed-off-by: Yury V. Zaytsev <yury@shurup.com>

configure.ac

@@ -705,6 +705,7 @@ tests/lib/mcconfig/Makefile
 tests/lib/search/Makefile
 tests/lib/strutil/Makefile
 tests/lib/vfs/Makefile
+tests/lib/vfs/mc.charsets
 tests/lib/widget/Makefile
 tests/src/Makefile
 tests/src/filemanager/Makefile

lib/strutil/strutil.c

@@ -57,18 +57,16 @@ static const char *const str_utf8_encodings[] = {
 
 /* standard 8bit encodings, no wide or multibytes characters */
 static const char *const str_8bit_encodings[] = {
-    /* Solaris has different names of Windows 1251 encoding */
-#ifdef __sun
-    "ansi-1251",
-    "ansi1251",
-#else
     "cp-1251",
     "cp1251",
-#endif
+    /* solaris */
+    "ansi-1251",
+    "ansi1251",
     "cp-1250",
     "cp1250",
     "cp-866",
     "cp866",
+    /* glibc */
     "ibm-866",
     "ibm866",
     "cp-850",

m4.include/mc-i18n.m4

@@ -18,16 +18,27 @@ AC_DEFUN([mc_I18N],[
         have_charset=yes
         charset_msg="yes"
 
+        AC_CHECK_HEADERS([gnu/libc-version.h])
+
         dnl Solaris has different name of Windows 1251 encoding
         case $host_os in
             solaris*)
-                CP1251="ANSI-1251"
+                ENCODING_CP1251="ANSI-1251"
                 ;;
             *)
-                CP1251="CP1251"
+                ENCODING_CP1251="CP1251"
                 ;;
         esac
 
-        AC_SUBST(CP1251)
+        if test "x$ac_cv_header_gnu_libc_version_h" != "xno"; then
+            ENCODING_CP866="IBM866"
+            ENCODING_ISO8859="ISO-8859"
+        else
+            ENCODING_CP866="CP866"
+            ENCODING_ISO8859="ISO8859"
+        fi
+
+        AC_SUBST(ENCODING_CP1251)
+        AC_SUBST(ENCODING_CP866)
     fi
 ])

misc/mc.charsets.in

@@ -1,13 +1,13 @@
 ASCII		7-bit ASCII
-ISO-8859-1	ISO 8859-1
+@ENCODING_ISO8859@-1	ISO 8859-1
-ISO-8859-2	ISO 8859-2
+@ENCODING_ISO8859@-2	ISO 8859-2
-ISO-8859-5	ISO 8859-5
+@ENCODING_ISO8859@-5	ISO 8859-5
 CP1250		Windows 1250
-@CP1251@		Windows 1251
+@ENCODING_CP1251@		Windows 1251
 CP437		CP 437
 CP850		CP 850
 CP852		CP 852
-IBM866		CP 866
+@ENCODING_CP866@		CP 866
 KOI8-R		KOI8-R
 KOI8-U		KOI8-U
 UTF-8		UTF-8

tests/lib/vfs/Makefile.am

@@ -1,7 +1,7 @@
 PACKAGE_STRING = "/lib/vfs"
 
 AM_CPPFLAGS = \
-	-DTEST_SHARE_DIR=\"$(abs_srcdir)\" \
+	-DTEST_SHARE_DIR=\"$(abs_builddir)\" \
 	$(GLIB_CFLAGS) \
 	-I$(top_srcdir) \
 	-I$(top_srcdir)/lib/vfs \
@@ -9,7 +9,11 @@ AM_CPPFLAGS = \
 
 AM_LDFLAGS = @TESTS_LDFLAGS@
 
-EXTRA_DIST = mc.charsets
+EXTRA_DIST = mc.charsets.in
+
+if CHARSET
+CLEANFILES = mc.charsets
+endif
 
 LIBS = @CHECK_LIBS@ \
 	$(top_builddir)/lib/libmc.la

tests/lib/vfs/mc.charsets.in

@@ -1,5 +1,5 @@
 ASCII		7-bit ASCII
-IBM866		CP 866
+@ENCODING_CP866@		CP 866
 KOI8-R		KOI8-R
 KOI8-U		KOI8-U
 UTF-8		UTF-8

tests/lib/vfs/path_cmp.c

@@ -48,8 +48,8 @@ setup (void)
     vfs_init_localfs ();
     vfs_setup_work_dir ();
 
-    mc_global.sysconfig_dir = (char *) TEST_SHARE_DIR;
 #ifdef HAVE_CHARSET
+    mc_global.sysconfig_dir = (char *) TEST_SHARE_DIR;
     load_codepages_list ();
 #endif
 }

tests/lib/vfs/path_len.c

@@ -48,8 +48,8 @@ setup (void)
     vfs_init_localfs ();
     vfs_setup_work_dir ();
 
-    mc_global.sysconfig_dir = (char *) TEST_SHARE_DIR;
 #ifdef HAVE_CHARSET
+    mc_global.sysconfig_dir = (char *) TEST_SHARE_DIR;
     load_codepages_list ();
 #endif
 }

tests/lib/vfs/path_manipulations.c

@@ -68,8 +68,8 @@ setup (void)
 
     init_test_classes ();
 
-    mc_global.sysconfig_dir = (char *) TEST_SHARE_DIR;
 #ifdef HAVE_CHARSET
+    mc_global.sysconfig_dir = (char *) TEST_SHARE_DIR;
     load_codepages_list ();
 #endif
 }

tests/lib/vfs/path_recode.c

@@ -71,8 +71,6 @@ test_init_vfs (const char *encoding)
     vfs_init_localfs ();
     vfs_setup_work_dir ();
 
-    mc_global.sysconfig_dir = (char *) TEST_SHARE_DIR;
-
     mc_global.sysconfig_dir = (char *) TEST_SHARE_DIR;
     load_codepages_list ();
 }

tests/lib/vfs/path_serialize.c

@@ -60,8 +60,8 @@ setup (void)
     vfs_init_class (&vfs_test_ops3, "testfs3", VFSF_UNKNOWN, "test3");
     vfs_register_class (&vfs_test_ops3);
 
-    mc_global.sysconfig_dir = (char *) TEST_SHARE_DIR;
 #ifdef HAVE_CHARSET
+    mc_global.sysconfig_dir = (char *) TEST_SHARE_DIR;
     load_codepages_list ();
 #endif
 }

tests/lib/vfs/relative_cd.c

@@ -84,8 +84,6 @@ setup (void)
     vfs_test_ops1->chdir = test_chdir;
     vfs_register_class (vfs_test_ops1);
 
-    mc_global.sysconfig_dir = (char *) TEST_SHARE_DIR;
-
     vfs_local_ops->chdir = test_chdir;
 
     test_chdir__init ();

tests/lib/vfs/vfs_get_encoding.c

@@ -112,8 +112,8 @@ static const struct test_vfs_get_encoding_ds
         NULL
     },
     { /* 14 */
-        "/aaaa/#enc:UTF-8/bbbb/#enc:KOI8-R#enc:IBM866/cccc",
+        "/aaaa/#enc:UTF-8/bbbb/#enc:KOI8-R#enc:CP866/cccc",
-        "KOI8-R#enc:IBM866"
+        "KOI8-R#enc:CP866"
     }
 };
 /* *INDENT-ON* */

tests/lib/vfs/vfs_path_string_convert.c

@@ -125,36 +125,36 @@ static const struct test_from_to_string_ds
         &vfs_test_ops3
     },
     { /* 4. */
-        "/#test1/bla-bla1/#enc:IBM866/some/path/#test2/bla-bla2/#enc:KOI8-R/some/path#test3/111/22/33",
+        "/#test1/bla-bla1/#enc:CP866/some/path/#test2/bla-bla2/#enc:KOI8-R/some/path#test3/111/22/33",
-        "/test1://#enc:IBM866/bla-bla1/some/path/test2://#enc:KOI8-R/bla-bla2/some/path/test3://111/22/33",
+        "/test1://#enc:CP866/bla-bla1/some/path/test2://#enc:KOI8-R/bla-bla2/some/path/test3://111/22/33",
         "111/22/33",
         4,
         &vfs_test_ops3
     },
     {  /* 5. */
-        "/#test1/bla-bla1/some/path/#test2/bla-bla2/#enc:IBM866/#enc:KOI8-R/some/path#test3/111/22/33",
+        "/#test1/bla-bla1/some/path/#test2/bla-bla2/#enc:CP866/#enc:KOI8-R/some/path#test3/111/22/33",
         "/test1://bla-bla1/some/path/test2://#enc:KOI8-R/bla-bla2/some/path/test3://111/22/33",
         "111/22/33",
         4,
         &vfs_test_ops3
     },
     { /* 6. */
-        "/#test1/bla-bla1/some/path/#test2/bla-bla2/#enc:IBM866/some/#enc:KOI8-R/path#test3/111/22/33",
+        "/#test1/bla-bla1/some/path/#test2/bla-bla2/#enc:CP866/some/#enc:KOI8-R/path#test3/111/22/33",
         "/test1://bla-bla1/some/path/test2://#enc:KOI8-R/bla-bla2/some/path/test3://111/22/33",
         "111/22/33",
         4,
         &vfs_test_ops3
     },
     { /* 7. */
-        "/#test1/bla-bla1/some/path/#test2/#enc:IBM866/bla-bla2/#enc:KOI8-R/some/path#test3/111/22/33",
+        "/#test1/bla-bla1/some/path/#test2/#enc:CP866/bla-bla2/#enc:KOI8-R/some/path#test3/111/22/33",
         "/test1://bla-bla1/some/path/test2://#enc:KOI8-R/bla-bla2/some/path/test3://111/22/33",
         "111/22/33",
         4,
         &vfs_test_ops3
     },
     { /* 8. */
-        "/#test1/bla-bla1/some/path/#enc:IBM866/#test2/bla-bla2/#enc:KOI8-R/some/path#test3/111/22/33",
+        "/#test1/bla-bla1/some/path/#enc:CP866/#test2/bla-bla2/#enc:KOI8-R/some/path#test3/111/22/33",
-        "/test1://#enc:IBM866/bla-bla1/some/path/test2://#enc:KOI8-R/bla-bla2/some/path/test3://111/22/33",
+        "/test1://#enc:CP866/bla-bla1/some/path/test2://#enc:KOI8-R/bla-bla2/some/path/test3://111/22/33",
         "111/22/33",
         4,
         &vfs_test_ops3