gdb.base/charset.{c,exp} C++ify

Adjust gdb.base/charset.{c,exp} so that the testcase works when
compiled as a C++ program.

wchar_t is built-in in C++, so don't make a phony typedef.

The "print /d" is so that we also get "1" instead of "true" in C++
mode.

gdb/testsuite/ChangeLog:

	* gdb.base/charset.c [__cplusplus] (wchar_t, char16_t, char32_t):
	Don't define.
	(utf_32_string): Compile for both C and C++.
	* gdb.base/charset.exp: Use "print /d".

gdb/testsuite/ChangeLog

@@ -1,3 +1,10 @@
+2020-09-17  Pedro Alves  <pedro@palves.net>
+
+	* gdb.base/charset.c [__cplusplus] (wchar_t, char16_t, char32_t):
+	Don't define.
+	(utf_32_string): Compile for both C and C++.
+	* gdb.base/charset.exp: Use "print /d".
+
 2020-09-17  Pedro Alves  <pedro@palves.net>
 
 	* gdb.base/watchpoint.c (buf): Make it 31 bytes.

gdb/testsuite/gdb.base/charset.c

@@ -49,11 +49,12 @@ char iso_8859_1_string[NUM_CHARS];
 char ebcdic_us_string[NUM_CHARS];
 char ibm1047_string[NUM_CHARS];
 
+#ifndef __cplusplus
+
 /* We make a phony wchar_t and then pretend that this platform uses
    UTF-32 (or UTF-16, depending on the size -- same difference for the
    purposes of this test).  */
 typedef unsigned int wchar_t;
-wchar_t utf_32_string[NUM_CHARS];
 
 /* We also define a couple phony types for testing the u'' and U''
    support.  It is ok if these have the wrong size on some platforms
@@ -61,6 +62,10 @@ wchar_t utf_32_string[NUM_CHARS];
 typedef unsigned short char16_t;
 typedef unsigned int char32_t;
 
+#endif
+
+wchar_t utf_32_string[NUM_CHARS];
+
 /* Make sure to use the typedefs.  */
 char16_t uvar;
 char32_t Uvar;

gdb/testsuite/gdb.base/charset.exp

@@ -409,7 +409,7 @@ foreach target_charset $charset_subset {
              "parse character literal in ${target_charset}"
 
     # Check that the character literal was encoded correctly.
-    gdb_test "print $L'A' == $var_name\[7\]" \
+    gdb_test "print /d $L'A' == $var_name\[7\]" \
              " = 1" \
              "check value of parsed character literal in ${target_charset}"
 
@@ -419,7 +419,7 @@ foreach target_charset $charset_subset {
              "parse string literal in ${target_charset}"
 
     # Check that the string literal was encoded correctly.
-    gdb_test "print $L\"q\"\[0\] == $var_name\[49\]" \
+    gdb_test "print /d $L\"q\"\[0\] == $var_name\[49\]" \
              " = 1" \
              "check value of parsed string literal in ${target_charset}"
 
@@ -470,12 +470,12 @@ foreach target_charset $charset_subset {
         if {$have_escape} {
 
             # Try parsing a backslash escape in a character literal.
-            gdb_test "print $L'\\${escape}' == $var_name\[$i\]" \
+            gdb_test "print /d $L'\\${escape}' == $var_name\[$i\]" \
                      " = 1" \
                      "check value of '\\${escape}' in ${target_charset}"
 
             # Try parsing a backslash escape in a string literal.
-            gdb_test "print $L\"\\${escape}\"\[0\] == $var_name\[$i\]" \
+            gdb_test "print /d $L\"\\${escape}\"\[0\] == $var_name\[$i\]" \
                      " = 1" \
                      "check value of \"\\${escape}\" in ${target_charset}"
         }
@@ -485,7 +485,7 @@ foreach target_charset $charset_subset {
     # get the unescaped character, in the target character set.
     gdb_test "print $L'\\q'" " = \[0-9-\]+ $L'q'" \
              "print escape that doesn't exist in $target_charset"
-    gdb_test "print $L'\\q' == $var_name\[49\]" " = 1" \
+    gdb_test "print /d $L'\\q' == $var_name\[49\]" " = 1" \
              "check value of escape that doesn't exist in $target_charset"
 }
 
@@ -585,7 +585,7 @@ if {$ucs2_ok} {
 }
 
 # Regression test for a cleanup bug in the charset code.
-gdb_test "print 'a' == 'a' || 'b' == 'b'" \
+gdb_test "print /d 'a' == 'a' || 'b' == 'b'" \
   ".* = 1" \
   "EVAL_SKIP cleanup handling regression test"