Avoid stray [] in ia64 assembler test.

Noted in <https://gcc.gnu.org/ml/gcc-patches/2018-11/msg00034.html>.
Fix by adding extra newline in test input is analogous to many such
newlines added in cases where argument to a newly added AC_LANG_SOURCE
had a preprocessor directive on its last line.

	* configure.ac (gcc_cv_as_ia64_ltoffx_ldxmov_relocs): Add newline
	at end of assembler input text.
	* configure: Regenerate.

From-SVN: r265724

gcc/ChangeLog

@@ -1,3 +1,9 @@
+2018-11-01  Joseph Myers  <joseph@codesourcery.com>
+
+	* configure.ac (gcc_cv_as_ia64_ltoffx_ldxmov_relocs): Add newline
+	at end of assembler input text.
+	* configure: Regenerate.
+
 2018-11-01  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/87826

gcc/configure

@@ -26646,7 +26646,8 @@ fi
     $as_echo '	.text
 	addl r15 = @ltoffx(x#), gp
 	;;
-	ld8.mov r16 = [r15], x#'[] > conftest.s
+	ld8.mov r16 = [r15], x#
+' > conftest.s
     if { ac_try='$gcc_cv_as $gcc_cv_as_flags  -o conftest.o conftest.s >&5'
   { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
   (eval $ac_try) 2>&5

gcc/configure.ac

@@ -4550,7 +4550,8 @@ gd:
 [	.text
 	addl r15 = @ltoffx(x#), gp
 	;;
-	ld8.mov r16 = [[r15]], x#],,
+	ld8.mov r16 = [[r15]], x#
+],,
     [AC_DEFINE(HAVE_AS_LTOFFX_LDXMOV_RELOCS, 1,
 	  [Define if your assembler supports ltoffx and ldxmov relocations.])])