Fix math_private.h multiple include guards.

Various math_private.h headers are guarded by "#ifndef
_MATH_PRIVATE_H", but never define the macro.  Nothing else defines
the macro either (the generic math_private.h that they include defines
a different macro, _MATH_PRIVATE_H_), so those guards are ineffective.

With the recent inclusion of s_sin.c in s_sincos.c, this breaks the
build for MIPS, since the build of s_sincos.c ends up including
<math_private.h> twice and the MIPS version defines inline functions
such as libc_feholdexcept_mips, without a separate fenv_private.h
header with its own guards such as some architectures have.

This patch fixes all the problem headers to use architecture-specific
guard macro names, and to define those macros in the headers they
guard, just as some architectures already do.

Tested for x86 (testsuite, and that installed shared libraries are
unchanged by the patch), and for mips64 (that it fixes the build).

	* sysdeps/arm/math_private.h [!_MATH_PRIVATE_H]: Change guard to
	[!ARM_MATH_PRIVATE_H].
	[!ARM_MATH_PRIVATE_H] (ARM_MATH_PRIVATE_H): Define macro.
	* sysdeps/hppa/math_private.h [!_MATH_PRIVATE_H]: Change guard to
	[!HPPA_MATH_PRIVATE_H].
	[!HPPA_MATH_PRIVATE_H] (HPPA_MATH_PRIVATE_H): Define macro.
	* sysdeps/i386/fpu/math_private.h [!_MATH_PRIVATE_H]: Change guard
	to [!I386_MATH_PRIVATE_H].
	[!I386_MATH_PRIVATE_H] (I386_MATH_PRIVATE_H): Define macro.
	* sysdeps/m68k/m680x0/fpu/math_private.h [!_MATH_PRIVATE_H]:
	Change guard to [!M68K_MATH_PRIVATE_H].
	[!M68K_MATH_PRIVATE_H] (M68K_MATH_PRIVATE_H): Define macro.
	* sysdeps/microblaze/math_private.h [!_MATH_PRIVATE_H]: Change
	guard to [!MICROBLAZE_MATH_PRIVATE_H].
	[!MICROBLAZE_MATH_PRIVATE_H] (MICROBLAZE_MATH_PRIVATE_H): Define
	macro.
	* sysdeps/mips/math_private.h [!_MATH_PRIVATE_H]: Change guard to
	[!MIPS_MATH_PRIVATE_H].
	[!MIPS_MATH_PRIVATE_H] (MIPS_MATH_PRIVATE_H): Define macro.
	* sysdeps/nios2/math_private.h [!_MATH_PRIVATE_H]: Change guard to
	[!NIO2_MATH_PRIVATE_H].
	[!NIO2_MATH_PRIVATE_H] (NIO2_MATH_PRIVATE_H): Define macro.
	* sysdeps/tile/math_private.h [!_MATH_PRIVATE_H]: Change guard to
	[!TILE_MATH_PRIVATE_H].
	[!TILE_MATH_PRIVATE_H] (TILE_MATH_PRIVATE_H): Define macro.

ChangeLog

@@ -1,5 +1,31 @@
 2015-11-20  Joseph Myers  <joseph@codesourcery.com>
 
+	* sysdeps/arm/math_private.h [!_MATH_PRIVATE_H]: Change guard to
+	[!ARM_MATH_PRIVATE_H].
+	[!ARM_MATH_PRIVATE_H] (ARM_MATH_PRIVATE_H): Define macro.
+	* sysdeps/hppa/math_private.h [!_MATH_PRIVATE_H]: Change guard to
+	[!HPPA_MATH_PRIVATE_H].
+	[!HPPA_MATH_PRIVATE_H] (HPPA_MATH_PRIVATE_H): Define macro.
+	* sysdeps/i386/fpu/math_private.h [!_MATH_PRIVATE_H]: Change guard
+	to [!I386_MATH_PRIVATE_H].
+	[!I386_MATH_PRIVATE_H] (I386_MATH_PRIVATE_H): Define macro.
+	* sysdeps/m68k/m680x0/fpu/math_private.h [!_MATH_PRIVATE_H]:
+	Change guard to [!M68K_MATH_PRIVATE_H].
+	[!M68K_MATH_PRIVATE_H] (M68K_MATH_PRIVATE_H): Define macro.
+	* sysdeps/microblaze/math_private.h [!_MATH_PRIVATE_H]: Change
+	guard to [!MICROBLAZE_MATH_PRIVATE_H].
+	[!MICROBLAZE_MATH_PRIVATE_H] (MICROBLAZE_MATH_PRIVATE_H): Define
+	macro.
+	* sysdeps/mips/math_private.h [!_MATH_PRIVATE_H]: Change guard to
+	[!MIPS_MATH_PRIVATE_H].
+	[!MIPS_MATH_PRIVATE_H] (MIPS_MATH_PRIVATE_H): Define macro.
+	* sysdeps/nios2/math_private.h [!_MATH_PRIVATE_H]: Change guard to
+	[!NIO2_MATH_PRIVATE_H].
+	[!NIO2_MATH_PRIVATE_H] (NIO2_MATH_PRIVATE_H): Define macro.
+	* sysdeps/tile/math_private.h [!_MATH_PRIVATE_H]: Change guard to
+	[!TILE_MATH_PRIVATE_H].
+	[!TILE_MATH_PRIVATE_H] (TILE_MATH_PRIVATE_H): Define macro.
+
 	[BZ #15421]
 	* sysdeps/ieee754/s_signgam.c (signgam): Rename to __signgam,
 	initialize with 0 and define as weak alias of __signgam.

sysdeps/arm/math_private.h

@@ -1,4 +1,5 @@
-#ifndef _MATH_PRIVATE_H
+#ifndef ARM_MATH_PRIVATE_H
+#define ARM_MATH_PRIVATE_H 1
 
 #include "fenv_private.h"
 #include_next <math_private.h>

sysdeps/hppa/math_private.h

@@ -16,7 +16,8 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#ifndef _MATH_PRIVATE_H
+#ifndef HPPA_MATH_PRIVATE_H
+#define HPPA_MATH_PRIVATE_H 1
 
 /* One of the few architectures where the meaning of the quiet/signaling bit is
    inverse to IEEE 754-2008 (as well as common practice for IEEE 754-1985).  */

sysdeps/i386/fpu/math_private.h

@@ -1,4 +1,5 @@
-#ifndef _MATH_PRIVATE_H
+#ifndef I386_MATH_PRIVATE_H
+#define I386_MATH_PRIVATE_H 1
 
 #include "fenv_private.h"
 #include_next <math_private.h>

sysdeps/m68k/m680x0/fpu/math_private.h

@@ -1,4 +1,5 @@
-#ifndef _MATH_PRIVATE_H
+#ifndef M68K_MATH_PRIVATE_H
+#define M68K_MATH_PRIVATE_H 1
 
 #define math_opt_barrier(x) \
 ({ __typeof (x) __x;					\

sysdeps/microblaze/math_private.h

@@ -1,4 +1,5 @@
-#ifndef _MATH_PRIVATE_H
+#ifndef MICROBLAZE_MATH_PRIVATE_H
+#define MICROBLAZE_MATH_PRIVATE_H 1
 
 /* Suppress use of exceptions here to avoid build errors if the FE_*
    macros aren't definied. Only allow rounding modes implemented for

sysdeps/mips/math_private.h

@@ -16,7 +16,8 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#ifndef _MATH_PRIVATE_H
+#ifndef MIPS_MATH_PRIVATE_H
+#define MIPS_MATH_PRIVATE_H 1
 
 #ifdef __mips_nan2008
 /* MIPS aligned to IEEE 754-2008.  */

sysdeps/nios2/math_private.h

@@ -1,4 +1,5 @@
-#ifndef _MATH_PRIVATE_H
+#ifndef NIO2_MATH_PRIVATE_H
+#define NIO2_MATH_PRIVATE_H 1
 
 /* Suppress use of exceptions here to avoid build errors if the FE_*
    macros aren't defined. Only allow rounding modes implemented for Nios II.

sysdeps/tile/math_private.h

@@ -1,4 +1,5 @@
-#ifndef _MATH_PRIVATE_H
+#ifndef TILE_MATH_PRIVATE_H
+#define TILE_MATH_PRIVATE_H 1
 
 /* Internally, we suppress any use of exception or rounding other
    than what is supported by the hardware.  This does mean that some