C++ compilability -- don't jump across variable initialization

C++ is picker than C about when you can "goto" across a variable being
defined.  The fix is to just minimize the variable's scope inside an
extra set of brackets.

Without this change, g++ has the following errors:

  transcode.c:590: error: jump to label 'resume_label3'
  transcode.c:514: error:   from here
  transcode.c:582: error:   crosses initialization of 'const unsigned char* p'
  transcode.c:2124: error: jump to label 'set_encs'
  transcode.c:2184: error:   from here
  transcode.c:2088: error:   skips initialization of 'const char* err'
  transcode.c:2089: error:   skips initialization of 'size_t error_len'
  transcode.c:2090: error:   skips initialization of 'mrb_value bytes'
  transcode.c:2091: error:   skips initialization of 'mrb_value dumped'
  transcode.c:2092: error:   skips initialization of 'size_t readagain_len'
  transcode.c:2093: error:   skips initialization of 'mrb_value bytes2'

1 files changed, 49 insertions, 44 deletions

diff --git a/src/transcode.c b/src/transcode.c
index ae78f20d4..e9d9b01ef 100644
--- a/src/transcode.c
+++ b/src/transcode.c
@@ -579,10 +579,12 @@ transcode_restartable0(mrb_state *mrb,
       switch (mrb_fixnum(next_info) & 0x1F) {
         case NOMAP:
             {
-                const unsigned char *p = inchar_start;
-                writebuf_off = 0;
-                while (p < in_p) {
-                    TRANSCODING_WRITEBUF(tc)[writebuf_off++] = (unsigned char)*p++;
+                {
+                    const unsigned char *p = inchar_start;
+                    writebuf_off = 0;
+                    while (p < in_p) {
+                        TRANSCODING_WRITEBUF(tc)[writebuf_off++] = (unsigned char)*p++;
+                    }
                 }
                 writebuf_len = writebuf_off;
                 writebuf_off = 0;
@@ -2085,51 +2087,54 @@ make_econv_exception(mrb_state *mrb, mrb_econv_t *ec)
     mrb_value mesg, exc;
     if (ec->last_error.result == econv_invalid_byte_sequence ||
         ec->last_error.result == econv_incomplete_input) {
-        const char *err = (const char *)ec->last_error.error_bytes_start;
-        size_t error_len = ec->last_error.error_bytes_len;
-        mrb_value bytes = mrb_str_new(mrb, err, error_len);
-        mrb_value dumped = mrb_str_dump(mrb, bytes);
-        size_t readagain_len = ec->last_error.readagain_len;
-        mrb_value bytes2 = mrb_nil_value();
-        mrb_value dumped2;
-        int idx;
-        if (ec->last_error.result == econv_incomplete_input) {
-            mesg = mrb_sprintf(mrb, "incomplete %s on %s",
-                    //StringValueCStr(dumped),
-                    mrb_string_value_cstr(mrb, &dumped),
-                    ec->last_error.source_encoding);
-        }
-        else if (readagain_len) {
-            bytes2 = mrb_str_new(mrb, err+error_len, readagain_len);
-            dumped2 = mrb_str_dump(mrb, bytes2);
-            mesg = mrb_sprintf(mrb, "%s followed by %s on %s",
-                    //StringValueCStr(dumped),
-                    mrb_string_value_cstr(mrb, &dumped),
-                    //StringValueCStr(dumped2),
-                    mrb_string_value_cstr(mrb, &dumped2),
-                    ec->last_error.source_encoding);
-        }
-        else {
-            mesg = mrb_sprintf(mrb, "%s on %s",
-                    //StringValueCStr(dumped),
-                    mrb_string_value_cstr(mrb, &dumped),
-                    ec->last_error.source_encoding);
+        {
+            const char *err = (const char *)ec->last_error.error_bytes_start;
+            size_t error_len = ec->last_error.error_bytes_len;
+            mrb_value bytes = mrb_str_new(mrb, err, error_len);
+            mrb_value dumped = mrb_str_dump(mrb, bytes);
+            size_t readagain_len = ec->last_error.readagain_len;
+            mrb_value bytes2 = mrb_nil_value();
+            mrb_value dumped2;
+            if (ec->last_error.result == econv_incomplete_input) {
+                mesg = mrb_sprintf(mrb, "incomplete %s on %s",
+                        //StringValueCStr(dumped),
+                        mrb_string_value_cstr(mrb, &dumped),
+                        ec->last_error.source_encoding);
+            }
+            else if (readagain_len) {
+                bytes2 = mrb_str_new(mrb, err+error_len, readagain_len);
+                dumped2 = mrb_str_dump(mrb, bytes2);
+                mesg = mrb_sprintf(mrb, "%s followed by %s on %s",
+                        //StringValueCStr(dumped),
+                        mrb_string_value_cstr(mrb, &dumped),
+                        //StringValueCStr(dumped2),
+                        mrb_string_value_cstr(mrb, &dumped2),
+                        ec->last_error.source_encoding);
+            }
+            else {
+                mesg = mrb_sprintf(mrb, "%s on %s",
+                        //StringValueCStr(dumped),
+                        mrb_string_value_cstr(mrb, &dumped),
+                        ec->last_error.source_encoding);
+            }
+    
+            exc = mrb_exc_new3(mrb, E_INVALIDBYTESEQUENCE_ERROR, mesg);
+            mrb_iv_set(mrb, exc, mrb_intern(mrb, "error_bytes"), bytes);
+            mrb_iv_set(mrb, exc, mrb_intern(mrb, "readagain_bytes"), bytes2);
+            mrb_iv_set(mrb, exc, mrb_intern(mrb, "incomplete_input"), ec->last_error.result == econv_incomplete_input ? mrb_true_value() : mrb_false_value());
         }
 
-        exc = mrb_exc_new3(mrb, E_INVALIDBYTESEQUENCE_ERROR, mesg);
-        mrb_iv_set(mrb, exc, mrb_intern(mrb, "error_bytes"), bytes);
-        mrb_iv_set(mrb, exc, mrb_intern(mrb, "readagain_bytes"), bytes2);
-        mrb_iv_set(mrb, exc, mrb_intern(mrb, "incomplete_input"), ec->last_error.result == econv_incomplete_input ? mrb_true_value() : mrb_false_value());
-
 set_encs:
         mrb_iv_set(mrb, exc, mrb_intern(mrb, "source_encoding_name"), mrb_str_new2(mrb, ec->last_error.source_encoding));
         mrb_iv_set(mrb, exc, mrb_intern(mrb, "destination_encoding_name"), mrb_str_new2(mrb, ec->last_error.destination_encoding));
-        idx = mrb_enc_find_index(mrb, ec->last_error.source_encoding);
-        if (0 <= idx)
-            mrb_iv_set(mrb, exc, mrb_intern(mrb, "source_encoding"), mrb_enc_from_encoding(mrb, mrb_enc_from_index(mrb, idx)));
-        idx = mrb_enc_find_index(mrb, ec->last_error.destination_encoding);
-        if (0 <= idx)
-            mrb_iv_set(mrb, exc, mrb_intern(mrb, "destination_encoding"), mrb_enc_from_encoding(mrb, mrb_enc_from_index(mrb, idx)));
+        {
+            int idx = mrb_enc_find_index(mrb, ec->last_error.source_encoding);
+            if (0 <= idx)
+                mrb_iv_set(mrb, exc, mrb_intern(mrb, "source_encoding"), mrb_enc_from_encoding(mrb, mrb_enc_from_index(mrb, idx)));
+            idx = mrb_enc_find_index(mrb, ec->last_error.destination_encoding);
+            if (0 <= idx)
+                mrb_iv_set(mrb, exc, mrb_intern(mrb, "destination_encoding"), mrb_enc_from_encoding(mrb, mrb_enc_from_index(mrb, idx)));
+        }
         return exc;
     }
     if (ec->last_error.result == econv_undefined_conversion) {