Autotools: Move openpty check to libraries section (#14737)

This is just a sync and alignment with Autoconf documentation style
order of checks in configure.ac ("Standard configure.ac Layout"):
https://www.gnu.org/software/autoconf/manual/autoconf-2.72/autoconf.html#Autoconf-Input-Layout

Author: petk

configure.ac

@@ -369,6 +369,10 @@ AC_SEARCH_LIBS([Pgrab], [proc])
 dnl Haiku does not have network api in libc.
 AC_SEARCH_LIBS([setsockopt], [network])
 
+dnl Check for openpty. It may require linking against libutil or libbsd.
+AC_CHECK_FUNCS([openpty],,
+  [AC_SEARCH_LIBS([openpty], [util bsd], [AC_DEFINE([HAVE_OPENPTY], [1])])])
+
 dnl Then headers.
 dnl ----------------------------------------------------------------------------
 
@@ -780,10 +784,6 @@ AS_VAR_IF([PHP_VALGRIND], [no],,
       AC_DEFINE([HAVE_VALGRIND], [1],
         [Define to 1 if Valgrind is enabled and supported.])])])
 
-dnl Check for openpty. It may require linking against libutil or libbsd.
-AC_CHECK_FUNCS([openpty],,
-  [AC_SEARCH_LIBS([openpty], [util bsd], [AC_DEFINE([HAVE_OPENPTY], [1])])])
-
 dnl General settings.
 dnl ----------------------------------------------------------------------------
 PHP_CONFIGURE_PART(General settings)