Moved 8 static error functions to sysdeps/common/error.c. This is the end

* include/glibtop/error.h: Moved 8 static error functions to
        sysdeps/common/error.c. This is the end of an big useless code
        bloat : expect ~8KB of object size reduction.

        * include/glibtop/procuid.h: s/int/gint32/g

        * lib/errors.c: (glibtop_error_quark):
        * lib/read.c: (do_read), (glibtop_read_l):
        * lib/read_data.c: (glibtop_read_data_l): Minor cleanups.

lib/errors.c

@@ -32,7 +32,7 @@ GQuark
 glibtop_error_quark (void)
 {
     static GQuark q = 0;
-    if (q == 0)
+    if (G_UNLIKELY(q == 0))
 	q = g_quark_from_static_string ("glibtop-error-quark");
 
     return q;