Move decoder of getpagesize syscall to libstrace

As only five architectures have getpagesize syscall, moving the decoder
to libstrace allows to get rid of getpagesize related ifdefs and check
build of getpagesize decoder on other architectures.

* mem.c (SYS_FUNC(getpagesize)): Move ...
* getpagesize.c: ... to this new file.
* Makefile.am (libstrace_a_SOURCES): Add it.

Makefile.am

@@ -72,6 +72,7 @@ libstrace_a_CFLAGS = $(strace_CFLAGS)
 libstrace_a_SOURCES =	\
 	fstatfs.c \
 	fstatfs64.c \
+	getpagesize.c \
 	ipc.c \
 	sigreturn.c	\
 	socketcall.c \

getpagesize.c

@@ -0,0 +1,6 @@
+#include "defs.h"
+
+SYS_FUNC(getpagesize)
+{
+	return RVAL_DECODED | RVAL_HEX;
+}

mem.c

@@ -330,14 +330,6 @@ SYS_FUNC(mincore)
 	return 0;
 }
 
-#if defined ALPHA || defined IA64 || defined M68K \
- || defined SPARC || defined SPARC64
-SYS_FUNC(getpagesize)
-{
-	return RVAL_DECODED | RVAL_HEX;
-}
-#endif
-
 SYS_FUNC(remap_file_pages)
 {
 	const kernel_ulong_t addr = tcp->u_arg[0];