diff --git a/configure.in b/configure.in
index 30c4a0333..1477b3bb3 100644
--- a/configure.in
+++ b/configure.in
@@ -600,17 +600,21 @@ AC_CHECK_HEADERS([assert.h crt_externs.h])
 #   DINFINITY - OSF specific
 #   DQNAN - OSF specific
 #       (DINFINITY and DQNAN are actually global variables, not functions)
+#   chsize - an MS-DOS-ism, found in mingw
 #   clog10 - not in mingw (though others like clog and csqrt are)
 #   fesetround - available in C99, but not older systems
+#   ftruncate - posix, but probably not older systems (current mingw
+#               has it as an inline for chsize)
 #   ioctl - not in mingw.
 #   gmtime_r - recent posix, not on old systems
 #   readdir_r - recent posix, not on old systems
 #   stat64 - SuS largefile stuff, not on old systems
 #   sysconf - not on old systems
+#   truncate - not in mingw
 #   isblank - available as a GNU extension or in C99
 #   _NSGetEnviron - Darwin specific
 #
-AC_CHECK_FUNCS([DINFINITY DQNAN clog10 ctermid fesetround ftime fchown getcwd geteuid gettimeofday gmtime_r ioctl lstat mkdir mknod nice readdir_r readlink rename rmdir select setegid seteuid setlocale setpgid setsid sigaction siginterrupt stat64 strftime strptime symlink sync sysconf tcgetpgrp tcsetpgrp times uname waitpid strdup system usleep atexit on_exit chown link fcntl ttyname getpwent getgrent kill getppid getpgrp fork setitimer getitimer strchr strcmp index bcopy memcpy rindex unsetenv isblank _NSGetEnviron])
+AC_CHECK_FUNCS([DINFINITY DQNAN chsize clog10 ctermid fesetround ftime ftruncate fchown getcwd geteuid gettimeofday gmtime_r ioctl lstat mkdir mknod nice readdir_r readlink rename rmdir select setegid seteuid setlocale setpgid setsid sigaction siginterrupt stat64 strftime strptime symlink sync sysconf tcgetpgrp tcsetpgrp times uname waitpid strdup system usleep atexit on_exit chown link fcntl ttyname getpwent getgrent kill getppid getpgrp fork setitimer getitimer strchr strcmp index bcopy memcpy rindex truncate unsetenv isblank _NSGetEnviron])
 
 # Reasons for testing:
 #   netdb.h - not in mingw