[committed] libstdc++: Fix -Wunused-variable from <regex>

[Jonathan Wakely]

In r16-4709-gc55c1de3a9adb2 I meant to use the result of the
static_cast<char> for the rest of the function following it, but I
accidentally used the original variable __ch. This causes
-Wunused-variable warnings for the __c initialized from the cast.

This fixes the rest of the function to use __c instead of __ch.

libstdc++-v3/ChangeLog:

	* include/bits/regex.tcc (regex_traits::value): Use __c instead
	of __ch.
---

Tested x86_64-linux. Pushed to trunk.

 libstdc++-v3/include/bits/regex.tcc | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/libstdc++-v3/include/bits/regex.tcc b/libstdc++-v3/include/bits/regex.tcc
index a0edf272717e..48917cdfda91 100644
--- a/libstdc++-v3/include/bits/regex.tcc
+++ b/libstdc++-v3/include/bits/regex.tcc
@@ -348,11 +348,11 @@ namespace __detail
 	{
 	  const char __c = static_cast<char>(__ch);
 	  const char __max_digit = __radix == 8 ? '7' : '9';
-	  if ('0' <= __ch && __ch <= __max_digit)
-	    return __ch - '0';
+	  if ('0' <= __c && __c <= __max_digit)
+	    return __c - '0';
 	  if (__radix < 16)
 	    return -1;
-	  switch (__ch)
+	  switch (__c)
 	  {
 	    case 'a':
 	    case 'A':
-- 
2.51.0