autotools: processed configure.ac through autoupdate

configure.ac

@@ -1,4 +1,4 @@
-AC_PREREQ(2.60)
+AC_PREREQ([2.60])
 
 AC_INIT([c-ares], [1.17.2],
   [c-ares mailing list: http://cool.haxx.se/mailman/listinfo/c-ares])
@@ -486,7 +486,15 @@ dnl Back to "normal" configuring
 dnl **********************************************************************
 
 dnl Checks for header files.
-AC_HEADER_STDC
+m4_warn([obsolete],
+[The preprocessor macro `STDC_HEADERS' is obsolete.
+  Except in unusual embedded environments, you can safely include all
+  ISO C90 headers unconditionally.])dnl
+# Autoupdate added the next two lines to ensure that your configure
+# script's behavior did not change.  They are probably safe to remove.
+AC_CHECK_INCLUDES_DEFAULT
+AC_PROG_EGREP
+
 
 CURL_CHECK_HEADER_MALLOC
 CURL_CHECK_HEADER_MEMORY
@@ -560,7 +568,20 @@ CARES_DEFINE_UNQUOTED([CARES_HAVE_ARPA_NAMESER_COMPAT_H])
 dnl Checks for typedefs, structures, and compiler characteristics.
 AC_C_CONST
 AC_TYPE_SIZE_T
-AC_HEADER_TIME
+m4_warn([obsolete],
+[Update your code to rely only on HAVE_SYS_TIME_H,
+then remove this warning and the obsolete code below it.
+All current systems provide time.h; it need not be checked for.
+Not all systems provide sys/time.h, but those that do, all allow
+you to include it and time.h simultaneously.])dnl
+AC_CHECK_HEADERS_ONCE([sys/time.h])
+# Obsolete code to be removed.
+if test $ac_cv_header_sys_time_h = yes; then
+  AC_DEFINE([TIME_WITH_SYS_TIME],[1],[Define to 1 if you can safely include both <sys/time.h>
+	     and <time.h>.  This macro is obsolete.])
+fi
+# End of obsolete code.
+
 CURL_CHECK_STRUCT_TIMEVAL
 
 AC_CHECK_TYPE(long long,
@@ -614,7 +635,19 @@ TYPE_SOCKADDR_STORAGE
 
 TYPE_SIG_ATOMIC_T
 
-AC_TYPE_SIGNAL
+m4_warn([obsolete],
+[your code may safely assume C89 semantics that RETSIGTYPE is void.
+Remove this warning and the `AC_CACHE_CHECK' when you adjust the code.])dnl
+AC_CACHE_CHECK([return type of signal handlers],[ac_cv_type_signal],[AC_COMPILE_IFELSE(
+[AC_LANG_PROGRAM([#include <sys/types.h>
+#include <signal.h>
+],
+		 [return *(signal (0, 0)) (0) == 1;])],
+		   [ac_cv_type_signal=int],
+		   [ac_cv_type_signal=void])])
+AC_DEFINE_UNQUOTED([RETSIGTYPE],[$ac_cv_type_signal],[Define as the return type of signal handlers
+		    (`int' or `void').])
+
 
 CURL_CHECK_FUNC_RECV
 CURL_CHECK_FUNC_RECVFROM