fix std hover, full capture terminator, bare static calls, void main in run-only images

- hover: a symbol from an embedded library source (tinyvm:std.zc, tinyvm:icon.zc) was
  looked up only in the document; look it up by its qualified name in the library source
  (hover_embedded_sym), and render a method found that way by its line (bs_hover).
- std.capture: allocate one word more than the 256 it holds, so end() terminates inside the buffer.
- a bare call to a static function of the enclosing struct resolves like a bare struct constant
  (mstruct is set for every non-generic struct's methods); the struct's own wins over a global.
- run.zc declares main untyped (fn main();), so a run-only image accepts int, void or untyped main
  with both compilers.

1 files changed, 3 insertions, 2 deletions

diff --git a/src/lib/std.zc b/src/lib/std.zc
index 33ab1e9..772b887 100644
--- a/src/lib/std.zc
+++ b/src/lib/std.zc
@@ -73,7 +73,8 @@ int libinit() {
 //   rt.put_s("hello world!");   // nothing on the terminal
 //   std.capture.end(buf);
 //   rt.put_s(buf);              // hello world!
-// the buffer holds 256 characters, and output past that is dropped.
+// the buffer holds 256 characters, and output past that is dropped. it has one
+// more word for the 0 that end() writes, so a full capture is still a string.
 // one capture at a time, and the buffer belongs to whoever holds it.
 struct capture {
 	// starts a capture: output goes into a new buffer instead of the terminal.
@@ -81,7 +82,7 @@ struct capture {
 	static char* start() {
 		int cap = 256;
 		rt.outmode = 2; rt.outn = 0; rt.outcap = cap;
-		rt.outbuf = rt.new(cap);
+		rt.outbuf = rt.new(cap + 1);
 		return rt.outbuf;
 	}
 	// stops the capture and ends the buffer with a 0.