Output: Generate location attributes for builtin declarations

Report a file id "f0" named "<builtin>" for declarations that are
generated by the compiler and have no reference location in the source.
Add a test case covering the MSVC builtin "size_t" typedef.

1 files changed, 1 insertions, 0 deletions

diff --git a/test/input/implicit-decl-ms.cxx b/test/input/implicit-decl-ms.cxx
new file mode 100644
index 0000000..47f16e8
--- /dev/null
+++ b/test/input/implicit-decl-ms.cxx
@@ -0,0 +1 @@
+size_t start(size_t);