ncurses 6.2 - patch 20210320

+ improve parameter-checking in tput by forcing it to analyze any
  extended string capability, e.g., as used in the Cs and Ms
  capabilities of the tmux description (report by Brad Town,
  cf: 20200531).
+ remove an incorrect free in the fallback (non-checking) version of
  _nc_free_and_exit (report by Miroslav Lichvar).
+ correct use-ordering in some xterm-direct flavors -TD
+ add hterm, hterm-256color (Mike Frysinger)
+ if the build-time compiler accepts c11's _Noreturn keyword, use that
  rather than gcc's attribute.
+ change configure-check for gcc's noreturn attribute to assume it is
  a prefix rather than suffix, matching c11's _Noreturn convention.
+ add "lint" rule to c++/Makefile, e.g., with cppcheck.

Ada95/aclocal.m4

@@ -29,7 +29,7 @@ dnl***************************************************************************
 dnl
 dnl Author: Thomas E. Dickey
 dnl
-dnl $Id: aclocal.m4,v 1.171 2021/01/06 01:29:44 tom Exp $
+dnl $Id: aclocal.m4,v 1.172 2021/03/20 16:31:13 tom Exp $
 dnl Macros used in NCURSES Ada95 auto-configuration script.
 dnl
 dnl These macros are maintained separately from NCURSES.  The copyright on
@@ -550,6 +550,33 @@ AC_SUBST(BUILD_EXEEXT)
 AC_SUBST(BUILD_OBJEXT)
 ])dnl
 dnl ---------------------------------------------------------------------------
+dnl CF_C11_NORETURN version: 1 updated: 2021/03/20 12:00:25
+dnl ---------------
+AC_DEFUN([CF_C11_NORETURN],
+[
+AC_CACHE_CHECK([for C11 _Noreturn feature], cf_cv_c11_noreturn,
+	[AC_TRY_COMPILE([
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdnoreturn.h>
+static void giveup(void) { exit(0); }
+	],
+	[if (feof(stdin)) giveup()],
+	cf_cv_c11_noreturn=yes,
+	cf_cv_c11_noreturn=no)
+	])
+
+if test "$cf_cv_c11_noreturn" = yes; then
+	AC_DEFINE(HAVE_STDNORETURN_H, 1)
+	AC_DEFINE_UNQUOTED(STDC_NORETURN,_Noreturn,[Define if C11 _Noreturn keyword is supported])
+	HAVE_STDNORETURN_H=1
+else
+	HAVE_STDNORETURN_H=0
+fi
+
+AC_SUBST(HAVE_STDNORETURN_H)
+])dnl
+dnl ---------------------------------------------------------------------------
 dnl CF_CC_ENV_FLAGS version: 10 updated: 2020/12/31 18:40:20
 dnl ---------------
 dnl Check for user's environment-breakage by stuffing CFLAGS/CPPFLAGS content
@@ -1274,13 +1301,14 @@ fi
 AC_SUBST(EXTRA_CFLAGS)
 ])dnl
 dnl ---------------------------------------------------------------------------
-dnl CF_GCC_ATTRIBUTES version: 23 updated: 2021/01/03 18:30:50
+dnl CF_GCC_ATTRIBUTES version: 24 updated: 2021/03/20 12:00:25
 dnl -----------------
 dnl Test for availability of useful gcc __attribute__ directives to quiet
 dnl compiler warnings.  Though useful, not all are supported -- and contrary
 dnl to documentation, unrecognized directives cause older compilers to barf.
 AC_DEFUN([CF_GCC_ATTRIBUTES],
 [AC_REQUIRE([AC_PROG_FGREP])dnl
+AC_REQUIRE([CF_C11_NORETURN])dnl
 
 if test "$GCC" = yes || test "$GXX" = yes
 then
@@ -1317,8 +1345,8 @@ cat > "conftest.$ac_ext" <<EOF
 #define GCC_SCANFLIKE(fmt,var)  /*nothing*/
 #endif
 extern void wow(char *,...) GCC_SCANFLIKE(1,2);
-extern void oops(char *,...) GCC_PRINTFLIKE(1,2) GCC_NORETURN;
-extern void foo(void) GCC_NORETURN;
+extern GCC_NORETURN void oops(char *,...) GCC_PRINTFLIKE(1,2);
+extern GCC_NORETURN void foo(void);
 int main(int argc GCC_UNUSED, char *argv[[]] GCC_UNUSED) { (void)argc; (void)argv; return 0; }
 EOF
 	cf_printf_attribute=no