powerpc64: maintain own linux/powerpc64 subdirectory

Most architectures supported by strace have their own subdirectory in
linux directory, but powerpc64 didn't, causing inconveniences.

* configure.ac (arch): Define to "powerpc64" on powerpc64.
* linux/powerpc/errnoent1.h: Move to linux/powerpc64/.
* linux/powerpc/ioctlent1.h: Likewise.
* linux/powerpc/signalent1.h: Likewise.
* linux/powerpc/syscallent1.h: Likewise.
* linux/powerpc64/ioctlent.h: New file.
* linux/powerpc64/syscallent.h: Likewise.
* linux/powerpc64/userent.h: Likewise.
* Makefile.am (EXTRA_DIST): Remove linux/powerpc/ioctlent1.h,
linux/powerpc/syscallent1.h, linux/powerpc/errnoent1.h, and
linux/powerpc/signalent1.h; added linux/powerpc64/errnoent1.h,
linux/powerpc64/ioctlent.h, linux/powerpc64/ioctlent1.h,
linux/powerpc64/signalent1.h, linux/powerpc64/syscallent.h,
linux/powerpc64/syscallent1.h, and linux/powerpc64/userent.h.
diff --git a/Makefile.am b/Makefile.am
index c303133..025af71 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -218,13 +218,16 @@
 	linux/or1k/syscallent.h		\
 	linux/or1k/userent.h		\
 	linux/personality.h		\
-	linux/powerpc/errnoent1.h	\
 	linux/powerpc/ioctlent.h.in	\
-	linux/powerpc/ioctlent1.h	\
-	linux/powerpc/signalent1.h	\
 	linux/powerpc/syscallent.h	\
-	linux/powerpc/syscallent1.h	\
 	linux/powerpc/userent.h		\
+	linux/powerpc64/errnoent1.h	\
+	linux/powerpc64/ioctlent.h	\
+	linux/powerpc64/ioctlent1.h	\
+	linux/powerpc64/signalent1.h	\
+	linux/powerpc64/syscallent.h	\
+	linux/powerpc64/syscallent1.h	\
+	linux/powerpc64/userent.h	\
 	linux/ptp_clock.h		\
 	linux/reboot.h			\
 	linux/s390/ioctlent.h.in	\
diff --git a/configure.ac b/configure.ac
index 56cf16d..c2e64f1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -52,13 +52,12 @@
 	AC_DEFINE([ALPHA], 1, [Define for the Alpha architecture.])
 	;;
 powerpc*)
-	arch=powerpc
 	AC_DEFINE([POWERPC], 1, [Define for the PowerPC architecture.])
 	AC_TRY_COMPILE(
 [#ifndef __LP64__
 # error 32 bit
-#endif], [], ppc_bits=64, ppc_bits=32)
-	if test "$ppc_bits" = "64"; then
+#endif], [], arch=powerpc64, arch=powerpc)
+	if test "$arch" = "powerpc64"; then
 		AC_DEFINE([POWERPC64], 1, [Define for the PowerPC64 architecture.])
 	fi
 	;;
diff --git a/linux/powerpc/ioctlent1.h b/linux/powerpc/ioctlent1.h
deleted file mode 100644
index 72eeaf1..0000000
--- a/linux/powerpc/ioctlent1.h
+++ /dev/null
@@ -1 +0,0 @@
-#include "ioctlent.h"
diff --git a/linux/powerpc/syscallent1.h b/linux/powerpc/syscallent1.h
deleted file mode 100644
index 49ccb8a..0000000
--- a/linux/powerpc/syscallent1.h
+++ /dev/null
@@ -1 +0,0 @@
-#include "syscallent.h"
diff --git a/linux/powerpc/errnoent1.h b/linux/powerpc64/errnoent1.h
similarity index 100%
rename from linux/powerpc/errnoent1.h
rename to linux/powerpc64/errnoent1.h
diff --git a/linux/powerpc64/ioctlent.h b/linux/powerpc64/ioctlent.h
new file mode 100644
index 0000000..df485d3
--- /dev/null
+++ b/linux/powerpc64/ioctlent.h
@@ -0,0 +1 @@
+#include "../ioctlent.h"
diff --git a/linux/powerpc64/ioctlent1.h b/linux/powerpc64/ioctlent1.h
new file mode 100644
index 0000000..df485d3
--- /dev/null
+++ b/linux/powerpc64/ioctlent1.h
@@ -0,0 +1 @@
+#include "../ioctlent.h"
diff --git a/linux/powerpc/signalent1.h b/linux/powerpc64/signalent1.h
similarity index 100%
rename from linux/powerpc/signalent1.h
rename to linux/powerpc64/signalent1.h
diff --git a/linux/powerpc64/syscallent.h b/linux/powerpc64/syscallent.h
new file mode 100644
index 0000000..64a9f01
--- /dev/null
+++ b/linux/powerpc64/syscallent.h
@@ -0,0 +1 @@
+#include "powerpc/syscallent.h"
diff --git a/linux/powerpc64/syscallent1.h b/linux/powerpc64/syscallent1.h
new file mode 100644
index 0000000..64a9f01
--- /dev/null
+++ b/linux/powerpc64/syscallent1.h
@@ -0,0 +1 @@
+#include "powerpc/syscallent.h"
diff --git a/linux/powerpc64/userent.h b/linux/powerpc64/userent.h
new file mode 100644
index 0000000..27c240b
--- /dev/null
+++ b/linux/powerpc64/userent.h
@@ -0,0 +1 @@
+#include "powerpc/userent.h"