library: removed all the 'PROCPS_' enumerator prefixes

Many of our item enumerator identifiers are very long,
especially in that <VMSTAT> module. Additionally, they
all contain the exact same universal 'PROCPS_' prefix.

The origins for this are likely found in the desire to
avoid name clashes with other potential include files.
But with procps-ng newlib, we've probably gone way too
far. Did 'PROCPS_PIDS_TICS_SYSTEM' actually offer more
protection against clash than 'PIDS_TICS_SYSTEM' does?

I don't think so. Besides, no matter how big that name
becomes, one can never guarantee they'll never be some
clash. And, conversely, extremely short names will not
always create conflict. Of course, in either case when
some clash occurs, one can always #undef that problem.

Thus, this commit will eliminate that 'PROCPS_' prefix
making all of those enum identifiers a little shorter.
And, we'll still be well above some ridiculously short
(criminally short) names found in some common headers:

- - - - - - - - - - <term.h>
- 'tab', 'TTY', etc
- - - - - - - - - - - - - - - - <search.h>
- 'ENTER', ENTRY', 'FIND', etc

------------------------------------------------------
Finally, with this as a last of the wholesale changes,
we will have established the naming conventions below:

. only functions will begin with that 'procps_' prefix
. exposed structures begin with the module/header name
. item enumerators begin like structs, but capitalized
. other enumerators work exactly like item enumerators
. macros and constants begin just like the enumerators
------------------------------------------------------

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

proc/vmstat.c

@@ -704,13 +704,13 @@ static struct {
   { RS(DELTA_WORKINGSET_REFAULT)            },
   { RS(DELTA_ZONE_RECLAIM_FAILED)           },
 
- // dummy entry corresponding to PROCPS_VMSTAT_logical_end ...
+ // dummy entry corresponding to VMSTAT_logical_end ...
   { NULL,                                   }
 };
 
     /* please note,
      * this enum MUST be 1 greater than the highest value of any enum */
-enum vmstat_item PROCPS_VMSTAT_logical_end = PROCPS_VMSTAT_DELTA_ZONE_RECLAIM_FAILED + 1;
+enum vmstat_item VMSTAT_logical_end = VMSTAT_DELTA_ZONE_RECLAIM_FAILED + 1;
 
 #undef setNAME
 #undef RS
@@ -726,7 +726,7 @@ static inline void assign_results (
 
     for (;;) {
         enum vmstat_item item = this->item;
-        if (item >= PROCPS_VMSTAT_logical_end)
+        if (item >= VMSTAT_logical_end)
             break;
         Item_table[item].setsfunc(this, hist);
         ++this;
@@ -739,9 +739,9 @@ static inline void cleanup_stack (
         struct vmstat_result *this)
 {
     for (;;) {
-        if (this->item >= PROCPS_VMSTAT_logical_end)
+        if (this->item >= VMSTAT_logical_end)
             break;
-        if (this->item > PROCPS_VMSTAT_noop)
+        if (this->item > VMSTAT_noop)
             this->result.ul_int = 0;
         ++this;
     }
@@ -802,18 +802,18 @@ static inline int items_check_failed (
      * offer any sort of warning like the following:
      *
      * warning: incompatible integer to pointer conversion passing 'int' to parameter of type 'enum vmstat_item *'
-     * my_stack = procps_vmstat_select(info, PROCPS_VMSTAT_noop, num);
+     * my_stack = procps_vmstat_select(info, VMSTAT_noop, num);
      *                                       ^~~~~~~~~~~~~~~~
      */
     if (numitems < 1
-    || (void *)items < (void *)(unsigned long)(2 * PROCPS_VMSTAT_logical_end))
+    || (void *)items < (void *)(unsigned long)(2 * VMSTAT_logical_end))
         return -1;
 
     for (i = 0; i < numitems; i++) {
         // a vmstat_item is currently unsigned, but we'll protect our future
         if (items[i] < 0)
             return -1;
-        if (items[i] >= PROCPS_VMSTAT_logical_end)
+        if (items[i] >= VMSTAT_logical_end)
             return -1;
     }
 
@@ -1176,7 +1176,7 @@ PROCPS_EXPORT struct vmstat_result *procps_vmstat_get (
 
     if (info == NULL)
         return NULL;
-    if (item < 0 || item >= PROCPS_VMSTAT_logical_end)
+    if (item < 0 || item >= VMSTAT_logical_end)
         return NULL;
 
     /* we will NOT read the vmstat file with every call - rather, we'll offer
@@ -1190,7 +1190,7 @@ PROCPS_EXPORT struct vmstat_result *procps_vmstat_get (
 
     info->get_this.item = item;
 //  with 'get', we must NOT honor the usual 'noop' guarantee
-//  if (item > PROCPS_VMSTAT_noop)
+//  if (item > VMSTAT_noop)
         info->get_this.result.ul_int = 0;
     Item_table[item].setsfunc(&info->get_this, &info->hist);
 
@@ -1219,11 +1219,11 @@ PROCPS_EXPORT struct vmstat_stack *procps_vmstat_select (
        if so, gotta' redo all of our stacks stuff ... */
     if (info->numitems != numitems + 1
     || memcmp(info->items, items, sizeof(enum vmstat_item) * numitems)) {
-        // allow for our PROCPS_VMSTAT_logical_end
+        // allow for our VMSTAT_logical_end
         if (!(info->items = realloc(info->items, sizeof(enum vmstat_item) * (numitems + 1))))
             return NULL;
         memcpy(info->items, items, sizeof(enum vmstat_item) * numitems);
-        info->items[numitems] = PROCPS_VMSTAT_logical_end;
+        info->items[numitems] = VMSTAT_logical_end;
         info->numitems = numitems + 1;
         if (info->extents)
             extents_free_all(info);