Output: Add the type of nullptr as a FundamentalType

Extend the `--castxml-output=1` format to support the nullptr type.
The name of the type is `decltype(nullptr)`.  Recognize types named
exactly this way (as a literal) and treat them as a FundamentalType.
This gives the `std::nullptr_t` typedef a meaningful representation even
without full decltype support.  Leave deeper nullptr-typed expressions
like `decltype((nullptr))` unchanged.

1 files changed, 4 insertions, 0 deletions

diff --git a/test/input/FundamentalType-nullptr.cxx b/test/input/FundamentalType-nullptr.cxx
new file mode 100644
index 0000000..867402e
--- /dev/null
+++ b/test/input/FundamentalType-nullptr.cxx
@@ -0,0 +1,4 @@
+namespace start {
+typedef decltype(nullptr) t_NullPtr;
+typedef decltype((nullptr)) t_ParenNullPtr;
+}