Kernel/LibC: Rework TIOC{G,S}WINSZ more linux like

Userspace can freely set terminal size, kernel just updates it when for
example new font is loaded. Also SIGWINCH is now sent by kernel instead
of userspace.

kernel/kernel/Terminal/TTY.cpp

@@ -184,6 +184,13 @@ namespace Kernel
 		return {};
 	}
 
+	void TTY::update_winsize(unsigned short cols, unsigned short rows)
+	{
+		m_winsize.ws_col = cols;
+		m_winsize.ws_row = rows;
+		(void)Process::kill(-m_foreground_pgrp, SIGWINCH);
+	}
+
 	BAN::ErrorOr<long> TTY::ioctl_impl(int request, void* argument)
 	{
 		switch (request)
@@ -198,8 +205,14 @@ namespace Kernel
 			case TIOCGWINSZ:
 			{
 				auto* winsize = static_cast<struct winsize*>(argument);
-				winsize->ws_col = width();
-				winsize->ws_row = height();
+				*winsize = m_winsize;
+				return 0;
+			}
+			case TIOCSWINSZ:
+			{
+				const auto* winsize = static_cast<const struct winsize*>(argument);
+				m_winsize = *winsize;
+				(void)Process::kill(-m_foreground_pgrp, SIGWINCH);
 				return 0;
 			}
 		}