all: check stdout and stderr status at exit

If stream status is not checked at the end of execution below problem
would not report error, or non-zero exit code.  The uptime is just an
example same was true with all commands of the project.

$ uptime >&- ; echo $?
uptime: write error: Bad file descriptor
1
$ uptime >/dev/full ; echo $?
uptime: write error: No space left on device
1

Signed-off-by: Sami Kerola <kerolasa@iki.fi>

top/Makefile.am

@@ -13,7 +13,8 @@ top_SOURCES =  \
 	top.h \
 	top.c \
 	top_nls.h \
-	top_nls.c
+	top_nls.c \
+	$(top_srcdir)/lib/fileutils.c
 
 dist_man_MANS = \
 	top.1