style: address syntax-check diagnostics

* examples/c/glr/c++-types.y: Formatting changes.
* po/POTFILES.in: Add missing files.
* src/reader.c: Remove useless include.
* tests/calc.at: Avoid magic values for exit.
Obfuscate calls to error.

po/POTFILES.in

@@ -14,6 +14,7 @@ src/main.c
 src/muscle-tab.c
 src/parse-gram.y
 src/print-graph.c
+src/print-xml.c
 src/print.c
 src/reader.c
 src/reduce.c