fix interaction of -S and -x {c,c++}-header

Irrespective of the use of -o this so far resulted in "error: output
filename specified twice", since cc1_options already produces a -o
option when -S was specified.

gcc/
2016-07-04  Jan Beulich  <jbeulich@suse.com>

	* gcc.c (default_compilers["@c-header"]): Conditionalize "-o".

gcc/cp/
2016-07-04  Jan Beulich  <jbeulich@suse.com>

	* lang-specs.h ("@c++-header"): Conditionalize "-o".

gcc/testsuite/
2016-07-04  Jan Beulich  <jbeulich@suse.com>

	* g++.dg/header.c: New.
	* gcc.dg/header.c: New.

From-SVN: r237955

gcc/ChangeLog

+2016-07-04  Jan Beulich  <jbeulich@suse.com>
+
+	* gcc.c (default_compilers["@c-header"]): Conditionalize "-o".
+
 2016-07-01  Michael Meissner  <meissner@linux.vnet.ibm.com>
 
 	PR target/71720

gcc/cp/ChangeLog

+2016-07-04  Jan Beulich  <jbeulich@suse.com>
+
+	* lang-specs.h ("@c++-header"): Conditionalize "-o".
+
 2016-06-29  Thomas Schwinge  <thomas@codesourcery.com>
 
 	* parser.c (cp_parser_pragma) <PRAGMA_OMP_CANCELLATION_POINT>:

gcc/cp/lang-specs.h

@@ -47,7 +47,7 @@ along with GCC; see the file COPYING3.  If not see
       cc1plus %{save-temps*|no-integrated-cpp:-fpreprocessed %{save-temps*:%b.ii} %{!save-temps*:%g.ii}}\
 	      %{!save-temps*:%{!no-integrated-cpp:%(cpp_unique_options)}}\
 	%(cc1_options) %2\
-	%{!fsyntax-only:-o %g.s \
+	%{!fsyntax-only:%{!S:-o %g.s} \
 	    %{!fdump-ada-spec*:%{!o*:--output-pch=%i.gch}\
 			       %W{o*:--output-pch=%*}}%V}}}}",
      CPLUSPLUS_CPP_SPEC, 0, 0},

gcc/gcc.c

@@ -1330,7 +1330,7 @@ static const struct compiler default_compilers[] =
 					       %W{o*:--output-pch=%*}}%V}}\
 	  %{!save-temps*:%{!traditional-cpp:%{!no-integrated-cpp:\
 		cc1 %(cpp_unique_options) %(cc1_options)\
-		    %{!fsyntax-only:-o %g.s \
+		    %{!fsyntax-only:%{!S:-o %g.s} \
 		        %{!fdump-ada-spec*:%{!o*:--output-pch=%i.gch}\
 					   %W{o*:--output-pch=%*}}%V}}}}}}}", 0, 0, 0},
   {".i", "@cpp-output", 0, 0, 0},

gcc/testsuite/ChangeLog

+2016-07-04  Jan Beulich  <jbeulich@suse.com>
+
+	* g++.dg/header.c: New.
+	* gcc.dg/header.c: New.
+
 2016-07-02  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c/71719

gcc/testsuite/g++.dg/header.C

+/* This really should use "dg-do compile" without the -S in dg-options,
+   but the extra options get put after the input file in that case, and
+   hence the test would fail. */
+/* { dg-do assemble } */
+/* { dg-options "-S -x c++-header" } */
+
+struct s {
+	unsigned field;
+};

gcc/testsuite/gcc.dg/header.c

+/* This really should use "dg-do compile" without the -S in dg-options,
+   but the extra options get put after the input file in that case, and
+   hence the test would fail. */
+/* { dg-do assemble } */
+/* { dg-options "-S -x c-header" } */
+
+struct s {
+	unsigned field;
+};