libstdc++: Qualify isdigit call to fix versioned namespace build.

	* src/c++11/random.cc: Include <cctype>.
	(random_devise::_M_init_pretr1): Qualify isdigit call.

From-SVN: r279271

libstdc++-v3/ChangeLog

+2019-12-12  François Dumont  <fdumont@gcc.gnu.org>
+
+	* src/c++11/random.cc: Include <cctype>.
+	(random_devise::_M_init_pretr1): Qualify isdigit call.
+
 2019-12-10  Thomas Rodgers  <trodgers@redhat.com>
 
 	* include/pstl/glue_numeric_defs.h: Restore enable_if lost during

libstdc++-v3/src/c++11/random.cc

@@ -41,6 +41,7 @@
 
 #include <cerrno>
 #include <cstdio>
+#include <cctype> // For std::isdigit.
 
 #if defined _GLIBCXX_HAVE_UNISTD_H && defined _GLIBCXX_HAVE_FCNTL_H
 # include <unistd.h>
@@ -286,7 +287,7 @@ namespace std _GLIBCXX_VISIBILITY(default)
     _M_mt.seed(seed);
 #else
     // Convert old default token "mt19937" or numeric seed tokens to "default".
-    if (token == "mt19937" || isdigit((unsigned char)token[0]))
+    if (token == "mt19937" || std::isdigit((unsigned char)token[0]))
       _M_init("default");
     else
       _M_init(token);