ECPG: Make the preprocessor emit ';' if the variable type for a list of

variables is varchar. This fixes this test case:

int main(void)
{
    exec sql begin declare section;
    varchar a[50], b[50];
    exec sql end declare section;

    return 0;
}

Since varchars are internally turned into custom structs and
the type name is emitted for these variable declarations,
the preprocessed code previously had:

struct varchar_1  { ... }  a _,_  struct varchar_2  { ... }  b ;

The comma in the generated C file was a syntax error.

There are no regression test changes since it's not exercised.

Patch by Boszormenyi Zoltan <zb@cybertec.at>

src/interfaces/ecpg/preproc/ecpg.trailer

@@ -837,7 +837,12 @@ opt_signed: SQL_SIGNED
 variable_list: variable
 			{ $$ = $1; }
 		| variable_list ',' variable
-			{ $$ = cat_str(3, $1, mm_strdup(","), $3); }
+		{
+			if (actual_type[struct_level].type_enum == ECPGt_varchar)
+				$$ = cat_str(3, $1, mm_strdup(";"), $3);
+			else
+				$$ = cat_str(3, $1, mm_strdup(","), $3);
+		}
 		;
 
 variable: opt_pointer ECPGColLabel opt_array_bounds opt_bit_field opt_initializer