library: refine support for multiple concurrent access

Our new library's now well protected against potential
problems which arise when a multi-threaded application
opens more than one context within the same API at the
same time. However, with a single-threaded application
designed along those same lines, some problems remain.

So, to avoid potential corruption of some data (which
was classified as local 'static __thread') from those
single-threaded designs, we'll move several variables
to the info structure itself and remove the '__thread'
qualifier. Now they're protected against both designs.

[ we'll not be protected against some multi-threaded ]
[ application that shares a single context yet calls ]
[ that interface from separate threads. this is just ]
[ bad application design & no different than sharing ]
[ other modifiable global data between such threads! ]

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

proc/stat.c

@@ -145,6 +145,7 @@ struct stat_info {
     struct stat_result get_this;       // for return to caller after a get
     struct item_support reap_items;    // items used for reap (shared among 3)
     struct item_support select_items;  // items unique to select
+    time_t sav_secs;                   // used by procps_stat_get to limit i/o
 };
 
 
@@ -990,7 +991,6 @@ PROCPS_EXPORT struct stat_result *procps_stat_get (
         struct stat_info *info,
         enum stat_item item)
 {
-    static __thread time_t sav_secs;
     time_t cur_secs;
 
     errno = EINVAL;
@@ -1003,10 +1003,10 @@ PROCPS_EXPORT struct stat_result *procps_stat_get (
     /* we will NOT read the source file with every call - rather, we'll offer
        a granularity of 1 second between reads ... */
     cur_secs = time(NULL);
-    if (1 <= cur_secs - sav_secs) {
+    if (1 <= cur_secs - info->sav_secs) {
         if (stat_read_failed(info))
             return NULL;
-        sav_secs = cur_secs;
+        info->sav_secs = cur_secs;
     }
 
     info->get_this.item = item;