Assume that we have utime() and <utime.h>.

These are required by POSIX since SUSv2, and no live platforms fail
to provide them.  On Windows, utime() exists and we bring our own
<utime.h>, so we're good there too.  So remove the configure probes
and ad-hoc substitute code.  We don't need to check for utimes()
anymore either, since that was only used as a substitute.

In passing, make the Windows build include <sys/utime.h> only where
we need it, not everywhere.

This is part of a series of commits to get rid of no-longer-relevant
configure checks and dead src/port/ code.  I'm committing them separately
to make it easier to back out individual changes if they prove less
portable than I expect.

Discussion: https://postgr.es/m/15379.1582221614@sss.pgh.pa.us

configure

@@ -12762,7 +12762,7 @@ $as_echo "#define HAVE_STDBOOL_H 1" >>confdefs.h
 fi
 
 
-for ac_header in atomic.h copyfile.h execinfo.h getopt.h ifaddrs.h langinfo.h mbarrier.h poll.h sys/epoll.h sys/event.h sys/ipc.h sys/prctl.h sys/procctl.h sys/pstat.h sys/resource.h sys/select.h sys/sem.h sys/shm.h sys/sockio.h sys/tas.h sys/un.h termios.h ucred.h utime.h wchar.h wctype.h
+for ac_header in atomic.h copyfile.h execinfo.h getopt.h ifaddrs.h langinfo.h mbarrier.h poll.h sys/epoll.h sys/event.h sys/ipc.h sys/prctl.h sys/procctl.h sys/pstat.h sys/resource.h sys/select.h sys/sem.h sys/shm.h sys/sockio.h sys/tas.h sys/un.h termios.h ucred.h wchar.h wctype.h
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"
@@ -14925,7 +14925,7 @@ fi
 LIBS_including_readline="$LIBS"
 LIBS=`echo "$LIBS" | sed -e 's/-ledit//g' -e 's/-lreadline//g'`
 
-for ac_func in backtrace_symbols clock_gettime copyfile fdatasync getifaddrs getpeerucred getrlimit kqueue mbstowcs_l memset_s poll posix_fallocate ppoll pstat pthread_is_threaded_np readlink setproctitle setproctitle_fast setsid shm_open strchrnul strsignal symlink sync_file_range uselocale utime utimes wcstombs_l
+for ac_func in backtrace_symbols clock_gettime copyfile fdatasync getifaddrs getpeerucred getrlimit kqueue mbstowcs_l memset_s poll posix_fallocate ppoll pstat pthread_is_threaded_np readlink setproctitle setproctitle_fast setsid shm_open strchrnul strsignal symlink sync_file_range uselocale wcstombs_l
 do :
   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
 ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"

configure.in

@@ -1300,7 +1300,6 @@ AC_CHECK_HEADERS(m4_normalize([
 	sys/un.h
 	termios.h
 	ucred.h
-	utime.h
 	wchar.h
 	wctype.h
 ]))
@@ -1642,8 +1641,6 @@ AC_CHECK_FUNCS(m4_normalize([
 	symlink
 	sync_file_range
 	uselocale
-	utime
-	utimes
 	wcstombs_l
 ]))
 

src/backend/libpq/pqcomm.c

@@ -81,9 +81,7 @@
 #ifdef HAVE_NETINET_TCP_H
 #include <netinet/tcp.h>
 #endif
-#ifdef HAVE_UTIME_H
 #include <utime.h>
-#endif
 #ifdef _MSC_VER					/* mstcpip.h is missing on mingw */
 #include <mstcpip.h>
 #endif
@@ -866,20 +864,8 @@ TouchSocketFiles(void)
 	{
 		char	   *sock_path = (char *) lfirst(l);
 
-		/*
-		 * utime() is POSIX standard, utimes() is a common alternative. If we
-		 * have neither, there's no way to affect the mod or access time of
-		 * the socket :-(
-		 *
-		 * In either path, we ignore errors; there's no point in complaining.
-		 */
-#ifdef HAVE_UTIME
-		utime(sock_path, NULL);
-#else							/* !HAVE_UTIME */
-#ifdef HAVE_UTIMES
-		utimes(sock_path, NULL);
-#endif							/* HAVE_UTIMES */
-#endif							/* HAVE_UTIME */
+		/* Ignore errors; there's no point in complaining */
+		(void) utime(sock_path, NULL);
 	}
 }
 

src/backend/utils/init/miscinit.c

@@ -26,9 +26,7 @@
 #include <pwd.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
-#ifdef HAVE_UTIME_H
 #include <utime.h>
-#endif
 
 #include "access/htup_details.h"
 #include "catalog/pg_authid.h"
@@ -1213,29 +1211,8 @@ TouchSocketLockFiles(void)
 		if (strcmp(socketLockFile, DIRECTORY_LOCK_FILE) == 0)
 			continue;
 
-		/*
-		 * utime() is POSIX standard, utimes() is a common alternative; if we
-		 * have neither, fall back to actually reading the file (which only
-		 * sets the access time not mod time, but that should be enough in
-		 * most cases).  In all paths, we ignore errors.
-		 */
-#ifdef HAVE_UTIME
-		utime(socketLockFile, NULL);
-#else							/* !HAVE_UTIME */
-#ifdef HAVE_UTIMES
-		utimes(socketLockFile, NULL);
-#else							/* !HAVE_UTIMES */
-		int			fd;
-		char		buffer[1];
-
-		fd = open(socketLockFile, O_RDONLY | PG_BINARY, 0);
-		if (fd >= 0)
-		{
-			read(fd, buffer, sizeof(buffer));
-			close(fd);
-		}
-#endif							/* HAVE_UTIMES */
-#endif							/* HAVE_UTIME */
+		/* we just ignore any error here */
+		(void) utime(socketLockFile, NULL);
 	}
 }
 

src/include/pg_config.h.in

@@ -662,15 +662,6 @@
 /* Define to 1 if you have the `uselocale' function. */
 #undef HAVE_USELOCALE
 
-/* Define to 1 if you have the `utime' function. */
-#undef HAVE_UTIME
-
-/* Define to 1 if you have the `utimes' function. */
-#undef HAVE_UTIMES
-
-/* Define to 1 if you have the <utime.h> header file. */
-#undef HAVE_UTIME_H
-
 /* Define to 1 if you have BSD UUID support. */
 #undef HAVE_UUID_BSD
 

src/include/port/win32_msvc/utime.h

@@ -1 +1,3 @@
 /* src/include/port/win32_msvc/utime.h */
+
+#include <sys/utime.h>			/* for non-unicode version */

src/include/port/win32_port.h

@@ -50,7 +50,6 @@
 #include <process.h>
 #include <signal.h>
 #include <direct.h>
-#include <sys/utime.h>			/* for non-unicode version */
 #undef near
 #include <sys/stat.h>			/* needed before sys/stat hacking below */
 

src/tools/msvc/Solution.pm

@@ -390,9 +390,6 @@ sub GenerateFiles
 		HAVE_UNIX_SOCKETS                        => undef,
 		HAVE_UNSETENV                            => undef,
 		HAVE_USELOCALE                           => undef,
-		HAVE_UTIME                               => 1,
-		HAVE_UTIMES                              => undef,
-		HAVE_UTIME_H                             => 1,
 		HAVE_UUID_BSD                            => undef,
 		HAVE_UUID_E2FS                           => undef,
 		HAVE_UUID_OSSP                           => undef,