move page helpers to common code

If you build with --disable-pcm, the rawmidi code fails to link because
it uses the page_size helper declared in local.h, but the page_* funcs
are in the pcm mmap module.  Move these funcs into conf.c so that they
are always available to the rest of the system.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

src/conf.c

@@ -4876,3 +4876,39 @@ static void _snd_config_end(void)
 	files_info_count = 0;
 }
 #endif
+
+size_t page_size(void)
+{
+	long s = sysconf(_SC_PAGE_SIZE);
+	assert(s > 0);
+	return s;
+}
+
+size_t page_align(size_t size)
+{
+	size_t r;
+	long psz = page_size();
+	r = size % psz;
+	if (r)
+		return size + psz - r;
+	return size;
+}
+
+size_t page_ptr(size_t object_offset, size_t object_size, size_t *offset, size_t *mmap_offset)
+{
+	size_t r;
+	long psz = page_size();
+	assert(offset);
+	assert(mmap_offset);
+	*mmap_offset = object_offset;
+	object_offset %= psz;
+	*mmap_offset -= object_offset;
+	object_size += object_offset;
+	r = object_size % psz;
+	if (r)
+		r = object_size + psz - r;
+	else
+		r = object_size;
+	*offset = object_offset;
+	return r;
+}