[testsuite] Fix bad dg-error syntax in gnu2x-attrs-1.c.

2019-11-21  Iain Sandoe  <iain@sandoe.co.uk>

	PR testsuite/92619
	* gcc.dg/gnu2x-attrs-1.c: Fix dg-error syntax.

From-SVN: r278594

gcc/testsuite/ChangeLog

+2019-11-21  Iain Sandoe  <iain@sandoe.co.uk>
+
+	PR testsuite/92619
+	* gcc.dg/gnu2x-attrs-1.c: Fix dg-error syntax.
+
 2019-11-21  Richard Sandiford  <richard.sandiford@arm.com>
 
 	PR tree-optimization/92526

gcc/testsuite/gcc.dg/gnu2x-attrs-1.c

@@ -5,7 +5,7 @@
 
 void f (void) {};
 
-[[gnu::alias("f")]] void g (void); /* { dg-error "only weak" *-*-darwin* } */
+[[gnu::alias("f")]] void g (void); /* { dg-error "only weak" "" { target *-*-darwin* } } */
 
 void [[gnu::alias("f")]] h (void); /* { dg-warning "ignored" } */
 /* { dg-message "that appertains to a type-specifier" "appertains" { target *-*-* } .-1 } */