uninitialized variable warnings

Description

I believe these warnings are actually false positives, but it's better to fix them nontheless.
They can be silenced by marking error-reporting functions as _noreturn_ (https://gcc.gnu.org/onlinedocs/gcc-4.7.2/gcc/Function-Attributes.html), or initialzing the offending variables.

```
external/cgns/src/tools/cgnscheck.c:402:9: warning: variable 'file_version' is used uninitialized whenever '||' condition is true [-Wsometimes-uninitialized]
if (cg_open (cgnsfile, CG_MODE_READ, &cgnsfn) ||
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
external/cgns/src/tools/cgnscheck.c:406:33: note: uninitialized use occurs here
if (LibraryVersion <= (int)(file_version * 1000.0 + 0.5)) {
^~~~~~~~~~~~
external/cgns/src/tools/cgnscheck.c:402:9: note: remove the '||' if its condition is always false
if (cg_open (cgnsfile, CG_MODE_READ, &cgnsfn) ||
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
external/cgns/src/tools/cgnscheck.c:396:23: note: initialize the variable 'file_version' to silence this warning
float file_version;
^
= 0.0
external/cgns/src/tools/cgnscheck.c:1142:9: warning: variable 'nodemap' is used uninitialized whenever switch default is taken [-Wsometimes-uninitialized]
default:
^~~~~~~
external/cgns/src/tools/cgnscheck.c:1145:23: note: uninitialized use occurs here
face = new_face (*nodemap++, NULL);
^~~~~~~
external/cgns/src/tools/cgnscheck.c:1021:17: note: initialize the variable 'nodemap' to silence this warning
int *nodemap;
^
= NULL
```

Environment

None

Assignee

Unassigned

Reporter

Anonymous

Components

Priority

Minor
Configure