ENH: handle 64-bit memory information (#3060)

- on large memory systems (eg, 6TB) the process information
  exceeds an 'int' range, so adjust parsing of the /proc/..
  to use int64

ENH: update/modernize OSspecific system information

ENH: minor update of profiling code

- std::string, noexcept, lazier evaluations

STYLE: use direct call of memInfo

applications/test/memInfo/Make/files

@@ -1,3 +1,3 @@
-Test-memInfo.C
+Test-memInfo.cxx
 
 EXE = $(FOAM_USER_APPBIN)/Test-memInfo

applications/test/memInfo/Test-memInfo.cxx

@@ -47,14 +47,18 @@ int main(int argc, char *argv[])
     memInfo mem;
 
     Info<< memTags << mem << endl;
-    List<vector> lst(n, vector::one);
 
-    Info<< "allocate " << n << " vectors" << nl
-        << memTags << mem.update() << endl;
+    List<vector> list(n, vector::one);
 
-    lst.clear();
-    Info<< "clear" << nl
-        << memTags << mem.update() << endl;
+    Info<< "allocate " << n << " vectors" << nl;
+    Info<< memTags << mem.update() << endl;
+
+    list.clear();
+    Info<< "clear" << nl;
+    Info<< memTags << mem.update() << endl;
+
+    mem.writeEntry("memory", Info);
+    Info<< endl;
 
     return 0;
 }