sysctl: relocate the procio code to a more proper home

Now that the procio logic was removed from the library
we must move the header file, lest we break make dist.

In the process, we will relocate that source file too.

[ we'll take a slightly different approach than that ]
[ used under the master branch by exploiting those 2 ]
[ non-library directories 'include' and 'lib', while ]
[ avoiding any sysctl hard coded function prototype. ]

Signed-off-by: Jim Warner <james.warner@comcast.net>

include/Makefile.am

@@ -2,6 +2,7 @@ dist_noinst_HEADERS = \
 	c.h \
 	fileutils.h \
 	nls.h \
+	procio.h \
 	rpmatch.h \
 	signals.h \
 	strutils.h \

include/procio.h

@@ -0,0 +1,8 @@
+#ifndef PROCPS_PROC_PROCIO_H
+#define PROCPS_PROC_PROCIO_H
+
+#include "procps.h"
+
+FILE *fprocopen(const char *, const char *);
+
+#endif