lib: add fileutils file with stream error checking facility

The close_stream() is copied from GNU lib. Inspiration to do this
is talk by Jim Meyering - Goodbye World! The perils of relying on
output streams in C.

Reference: http://www.irill.org/events/ghm-gnu-hackers-meeting/videos/jim-meyering-goodbye-world-the-perils-of-relying-on-output-streams-in-c
Signed-off-by: Sami Kerola <kerolasa@iki.fi>

include/fileutils.h

@@ -0,0 +1,7 @@
+#ifndef PROCPS_NG_FILEUTILS
+#define PROCPS_NG_FILEUTILS
+
+int close_stream(FILE * stream);
+void close_stdout(void);
+
+#endif