Fix issue 146

Fix return value when handling WM_SETCURSOR.  Returning FALSE
indicating we didn't handle it stopped the cursor from being set
to the size arrow cursors.  Instead, pass it to DefWindowProc().

While we're here, handle WM_SIZING to make it more clear that you
can't change the aspect ratio by dragging.

src/conio/OverhaulNotes.txt

@@ -131,3 +131,19 @@ http://viznut.fi/unscii/
 
 Unifont... the mother of all fonts...
 https://unifoundry.com/unifont/index.html
+
+For Unicode, we're not going to want the fonts in the image I don't
+think, so they'll need to be loaded from disk/rasterized on demand.
+This means a cache that we can use bsearch() on... which means we'll
+need something like an epoch to age things out of the cache, and the
+cache will need to be cleared after each connection... and presumably
+at certain other points during a connection.  Getting this right with
+epoch stuff is going to prove tricky, but be necessary to prevent
+blocking while waiting to render a glyph (essentially, it must *always*
+be possible to add a new glyph without blocking).
+
+Further, "fonts" will need to have a source map as well... loading
+a CP437 font will only update specific glyphs for example, and those
+will be spread out around the space, so "stacks" of fonts, each
+entry listing ranges to map will be needed, and we'll want to use
+bsearch() there too.

src/conio/win32gdi.c

@@ -271,6 +271,51 @@ gdi_handle_wm_size(WPARAM wParam, LPARAM lParam)
 	return 0;
 }
 
+static LRESULT
+gdi_handle_wm_sizing(WPARAM wParam, RECT *r)
+{
+	int ow, oh, nw, nh;
+	double s;
+	RECT tr = *r;
+
+	ow = r->right - r->left;
+	oh = r->bottom - r->top;
+	UnadjustWindowSize(&ow, &oh);
+	nw = ow;
+	nh = oh;
+	pthread_mutex_lock(&vstatlock);
+	s = bitmap_double_mult_inside(ow, oh);
+	bitmap_get_scaled_win_size(s, &nw, &nh, 0, 0);
+	pthread_mutex_unlock(&vstatlock);
+
+	if (nw != ow) {
+		switch (wParam) {
+			case WMSZ_BOTTOMLEFT:
+			case WMSZ_LEFT:
+			case WMSZ_TOPLEFT:
+				r->left += (nw - ow);
+				break;
+			default:
+				r->right += (nw - ow);
+				break;
+		}
+	}
+	if (nh != oh) {
+		switch (wParam) {
+			case WMSZ_TOP:
+			case WMSZ_TOPLEFT:
+			case WMSZ_TOPRIGHT:
+				r->top += (nh - oh);
+				break;
+			default:
+				r->bottom += (nh - oh);
+				break;
+		}
+	}
+
+	return TRUE;
+}
+
 static LRESULT
 gdi_handle_wm_paint(HWND hwnd)
 {
@@ -646,6 +691,8 @@ gdi_WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
 			return 0;
 		case WM_SIZE:
 			return gdi_handle_wm_size(wParam, lParam);
+		case WM_SIZING:
+			return gdi_handle_wm_sizing(wParam, (RECT *)lParam);
 		case WM_CLOSE:
 		case WM_DESTROY:
 			PostQuitMessage(0);
@@ -675,7 +722,7 @@ gdi_WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
 				SetCursor(cursor);
 				return TRUE;
 			}
-			return FALSE;
+			break;
 		case WM_GETDPISCALEDSIZE:
 			return gdi_handle_getdpiscaledsize(HIWORD(wParam), (LPSIZE)lParam);
 		case WM_DPICHANGED: