c variadic calls

README.md

@@ -45,6 +45,18 @@ pointers to opaque records. They never add linker inputs; implementations must
 still be supplied explicitly with the C-prefixed linking options. Set
 `BROLANG_LIBCLANG_PATH` when libclang is not installed in a standard location.
 
+Bodyless manual and imported C functions may be variadic:
+
+```bro
+log_values :: c_func(tag c_int, ...) c_int
+```
+
+Arguments after `...` accept concrete scalars, pointers, and nullable pointers.
+Narrow integers are promoted to the target C `int` or `unsigned int`, and
+`f32`/`c_float` are promoted to `c_double`. Arrays, slices, structs, and other
+compound values must be converted to an explicit C-compatible representation
+before the call.
+
 Compilation phases are isolated under `compiler/`:
 
 ```text
@@ -83,6 +95,7 @@ Current prototype features:
 - Qualified imported globals and functions with package-aware symbol mangling
 - Demand-monomorphized Brolang and C-ABI functions
 - Bodyless concrete C function declarations with exact external symbol names
+- Bodyless manual and imported C variadic declarations with default argument promotions
 - Ordered linking of additional C sources, objects, archives, and libraries
 - Checked signed addition and unary negation
 - Static, eager runtime, and deferred problematic globals