libdecnumber: Modify dconfig.h to Integrate with QEMU

Modify the dconfig.h header file so that libdecnumber code integrates QEMU
configuration.   Specifically:

  - the WORDS_BIGENDIAN preprocessor macro is used in libdecnumber code to
    determines endianness.  It is derived from the existing QEMU macro
    HOST_WORDS_BIGENDIAN which is defined in config-host.h.

  - the DECPUN macro determines the number of decimal digits (aka declets) per
    unit (byte).  This is 3 for PowerPC DFP.
Signed-off-by: NTom Musta <tommusta@gmail.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

include/libdecnumber/dconfig.h

@@ -27,26 +27,14 @@
    Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
    02110-1301, USA.  */
 
-#ifdef IN_LIBGCC2
+#include "config-host.h"
 
-#include "tconfig.h"
-#include "coretypes.h"
-#include "tm.h"
-
-#ifndef LIBGCC2_WORDS_BIG_ENDIAN
-#define LIBGCC2_WORDS_BIG_ENDIAN WORDS_BIG_ENDIAN
-#endif
-
-#ifndef LIBGCC2_FLOAT_WORDS_BIG_ENDIAN
-#define LIBGCC2_FLOAT_WORDS_BIG_ENDIAN LIBGCC2_WORDS_BIG_ENDIAN
-#endif
-
-#if LIBGCC2_FLOAT_WORDS_BIG_ENDIAN
+#if defined(HOST_WORDS_BIGENDIAN)
 #define WORDS_BIGENDIAN 1
-#endif
-
 #else
+#define WORDS_BIGENDIAN 0
+#endif
 
-#include "config.h"
-
+#ifndef DECDPUN
+#define DECDPUN 3
 #endif