Regenerate configure script with autoconf 2.71.

Also fix some warnings from the new version.

config.h.in

@@ -547,9 +547,6 @@
 /* Define to 1 if you have the <maillock.h> header file. */
 #undef HAVE_MAILLOCK_H
 
-/* Define to 1 if you have the <memory.h> header file. */
-#undef HAVE_MEMORY_H
-
 /* Define to 1 if you have the `memrchr' function. */
 #undef HAVE_MEMRCHR
 
@@ -559,6 +556,9 @@
 /* Define to 1 if you have the `memset_s' function. */
 #undef HAVE_MEMSET_S
 
+/* Define to 1 if you have the <minix/config.h> header file. */
+#undef HAVE_MINIX_CONFIG_H
+
 /* Define to 1 if you have the `mkdtemp' function. */
 #undef HAVE_MKDTEMP
 
@@ -784,6 +784,9 @@
 /* Define to 1 if you have the <stdint.h> header file. */
 #undef HAVE_STDINT_H
 
+/* Define to 1 if you have the <stdio.h> header file. */
+#undef HAVE_STDIO_H
+
 /* Define to 1 if you have the <stdlib.h> header file. */
 #undef HAVE_STDLIB_H
 
@@ -969,6 +972,9 @@
 /* Define to 1 if you have the `vsyslog' function. */
 #undef HAVE_VSYSLOG
 
+/* Define to 1 if you have the <wchar.h> header file. */
+#undef HAVE_WCHAR_H
+
 /* Define to 1 if you have the `wordexp' function. */
 #undef HAVE_WORDEXP
 
@@ -1184,7 +1190,9 @@
    */
 #undef STATIC_SUDOERS_PLUGIN
 
-/* Define to 1 if you have the ANSI C header files. */
+/* Define to 1 if all of the C90 standard headers exist (not just the ones
+   required in a freestanding environment). This macro is provided for
+   backward compatibility; new code need not use it. */
 #undef STDC_HEADERS
 
 /* Define to 1 if the code in interfaces.c does not compile for you. */
@@ -1231,32 +1239,93 @@
 #ifndef _ALL_SOURCE
 # undef _ALL_SOURCE
 #endif
-/* Enable GNU extensions on systems that have them.  */
+/* Enable general extensions on macOS.  */
-#ifndef _GNU_SOURCE
+#ifndef _DARWIN_C_SOURCE
-# undef _GNU_SOURCE
+# undef _DARWIN_C_SOURCE
-#endif
-/* Enable threading extensions on Solaris.  */
-#ifndef _POSIX_PTHREAD_SEMANTICS
-# undef _POSIX_PTHREAD_SEMANTICS
-#endif
-/* Enable extensions on HP NonStop.  */
-#ifndef _TANDEM_SOURCE
-# undef _TANDEM_SOURCE
 #endif
 /* Enable general extensions on Solaris.  */
 #ifndef __EXTENSIONS__
 # undef __EXTENSIONS__
 #endif
+/* Enable GNU extensions on systems that have them.  */
+#ifndef _GNU_SOURCE
+# undef _GNU_SOURCE
+#endif
+/* Enable X/Open compliant socket functions that do not require linking
+   with -lxnet on HP-UX 11.11.  */
+#ifndef _HPUX_ALT_XOPEN_SOCKET_API
+# undef _HPUX_ALT_XOPEN_SOCKET_API
+#endif
+/* Identify the host operating system as Minix.
+   This macro does not affect the system headers' behavior.
+   A future release of Autoconf may stop defining this macro.  */
+#ifndef _MINIX
+# undef _MINIX
+#endif
+/* Enable general extensions on NetBSD.
+   Enable NetBSD compatibility extensions on Minix.  */
+#ifndef _NETBSD_SOURCE
+# undef _NETBSD_SOURCE
+#endif
+/* Enable OpenBSD compatibility extensions on NetBSD.
+   Oddly enough, this does nothing on OpenBSD.  */
+#ifndef _OPENBSD_SOURCE
+# undef _OPENBSD_SOURCE
+#endif
+/* Define to 1 if needed for POSIX-compatible behavior.  */
+#ifndef _POSIX_SOURCE
+# undef _POSIX_SOURCE
+#endif
+/* Define to 2 if needed for POSIX-compatible behavior.  */
+#ifndef _POSIX_1_SOURCE
+# undef _POSIX_1_SOURCE
+#endif
+/* Enable POSIX-compatible threading on Solaris.  */
+#ifndef _POSIX_PTHREAD_SEMANTICS
+# undef _POSIX_PTHREAD_SEMANTICS
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-5:2014.  */
+#ifndef __STDC_WANT_IEC_60559_ATTRIBS_EXT__
+# undef __STDC_WANT_IEC_60559_ATTRIBS_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-1:2014.  */
+#ifndef __STDC_WANT_IEC_60559_BFP_EXT__
+# undef __STDC_WANT_IEC_60559_BFP_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-2:2015.  */
+#ifndef __STDC_WANT_IEC_60559_DFP_EXT__
+# undef __STDC_WANT_IEC_60559_DFP_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-4:2015.  */
+#ifndef __STDC_WANT_IEC_60559_FUNCS_EXT__
+# undef __STDC_WANT_IEC_60559_FUNCS_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-3:2015.  */
+#ifndef __STDC_WANT_IEC_60559_TYPES_EXT__
+# undef __STDC_WANT_IEC_60559_TYPES_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TR 24731-2:2010.  */
+#ifndef __STDC_WANT_LIB_EXT2__
+# undef __STDC_WANT_LIB_EXT2__
+#endif
+/* Enable extensions specified by ISO/IEC 24747:2009.  */
+#ifndef __STDC_WANT_MATH_SPEC_FUNCS__
+# undef __STDC_WANT_MATH_SPEC_FUNCS__
+#endif
+/* Enable extensions on HP NonStop.  */
+#ifndef _TANDEM_SOURCE
+# undef _TANDEM_SOURCE
+#endif
+/* Enable X/Open extensions.  Define to 500 only if necessary
+   to make mbstate_t available.  */
+#ifndef _XOPEN_SOURCE
+# undef _XOPEN_SOURCE
+#endif
 
 
 /* Define to avoid using the passwd/shadow file for authentication. */
 #undef WITHOUT_PASSWD
 
-/* Enable large inode numbers on Mac OS X 10.5.  */
-#ifndef _DARWIN_USE_64_BIT_INODE
-# define _DARWIN_USE_64_BIT_INODE 1
-#endif
-
 /* Number of bits in a file offset, on hosts where this is settable. */
 #undef _FILE_OFFSET_BITS
 
@@ -1267,16 +1336,6 @@
 /* Define for large files, on AIX-style hosts. */
 #undef _LARGE_FILES
 
-/* Define to 1 if on MINIX. */
-#undef _MINIX
-
-/* Define to 2 if the system does not provide POSIX.1 features except with
-   this defined. */
-#undef _POSIX_1_SOURCE
-
-/* Define to 1 if you need to in order for `stat' and other things to work. */
-#undef _POSIX_SOURCE
-
 /* Define to __FUNCTION__ if your compiler supports __FUNCTION__ but not
    __func__ */
 #undef __func__

configure.ac

@@ -2431,7 +2431,6 @@ fi
 dnl
 dnl C compiler checks (to be done after os checks)
 dnl
-AC_PROG_CC_STDC
 AC_C_CONST
 AC_C_INLINE
 AC_C_VOLATILE
@@ -4042,12 +4041,36 @@ if test ${with_passwd-'no'} != "no"; then
 	_LIBS="$LIBS"
 	LIBS="$LIBS $shadow_libs"
 	found=no
-	AC_CHECK_FUNCS([$shadow_funcs], [found=yes])
+	for func in $shadow_funcs; do
-	if test "$found" = "yes"; then
+	    AC_CHECK_FUNC([$func], [
-	    case "$shadow_funcs" in
+		dnl Enumerate shadow functions instead of using:
-		*getprpwnam*) SECUREWARE=1;;
+		dnl     AC_DEFINE_UNQUOTED(AS_TR_CPP([HAVE_$func]))
-	    esac
+		dnl for autoheader's sake and to catch template omissions.
-	else
+		case "$func" in
+		    dispcrypt)
+			AC_DEFINE(HAVE_DISPCRYPT)
+			;;
+		    getprpwnam)
+			AC_DEFINE(HAVE_GETPRPWNAM)
+			SECUREWARE=1
+			;;
+		    getpwnam_shadow)
+			AC_DEFINE(HAVE_GETPWNAM_SHADOW)
+			;;
+		    getspnam)
+			AC_DEFINE(HAVE_GETSPNAM)
+			;;
+		    iscomsec)
+			AC_DEFINE(HAVE_ISCOMSEC)
+			;;
+		    *)
+			AC_MSG_ERROR([unhandled shadow password function $func])
+			;;
+		esac
+		found=yes
+	    ])
+	done
+	if test "$found" = "no"; then
 	    shadow_libs=
 	fi
 	CHECKSHADOW=false