patch 8.2.1570: configure check for dirfd() does not work on HPUX

Problem:    Configure check for dirfd() does not work on HPUX. (Michael Osipov)
Solution:   Use AC_TRY_LINK instead of AC_TRY_COMPILE. (closes #6838)
diff --git a/src/auto/configure b/src/auto/configure
index c85dec9..e66162f 100755
--- a/src/auto/configure
+++ b/src/auto/configure
@@ -13771,7 +13771,7 @@
   return 0;
 }
 _ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
+if ac_fn_c_try_link "$LINENO"; then :
   { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }; $as_echo "#define HAVE_DIRFD 1" >>confdefs.h
 
@@ -13779,7 +13779,8 @@
   { $as_echo "$as_me:${as_lineno-$LINENO}: result: not usable" >&5
 $as_echo "not usable" >&6; }
 fi
-rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for flock" >&5
 $as_echo_n "checking for flock... " >&6; }
@@ -13794,7 +13795,7 @@
   return 0;
 }
 _ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
+if ac_fn_c_try_link "$LINENO"; then :
   { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }; $as_echo "#define HAVE_FLOCK 1" >>confdefs.h
 
@@ -13802,7 +13803,8 @@
   { $as_echo "$as_me:${as_lineno-$LINENO}: result: not usable" >&5
 $as_echo "not usable" >&6; }
 fi
-rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for sysctl" >&5
 $as_echo_n "checking for sysctl... " >&6; }