Some libraries that depend on devdraw don't know about 32x32 cursor -- mainly 9fans.net/go/draw.

It is possible to receive multiple screen resize events, and resizeimg would be called for different sizes, before _flushmemscreen actually gets called with rectangle sizes different from the most recent resizeimg call. The size mismatch would trigger illegal memory access inside _flushmemscreen. This commit protects _flushmemscreen by returning early if the requested rectangle is outside of the current texture rectangle.

Fixes bug where devdraw does not "notice" mouse position after task switch. Fixes https://github.com/9fans/plan9port/issues/232.

Fixes #235.

Auto-indent mode leaves trailing spaces on blank lines as you type past them, so silently elide them from the window content as it gets written back to disk. Another option would be to remove them from the window entirely during Put, but they're actually nice to have while editing, and to date Put has never modified the window content.

FreeBSD 11.2 by default does not have gcc.

Use the widely accepted /dev/stdout.

My MacBook Pro has hw.ncpu=12, so set NPROC=12. Speeds up INSTALL dramatically. Should probably add similar code to other OSes. Also silence rio warning from earlier commit.

If $font is not set, the default font is constructed from font data linked into every libdraw binary. That process was different from the usual openfont code, and so it was not hidpi-aware, resulting in very tiny fonts out of the box on hidpi systems, until users set $font. Fix this by using openfont to construct the default font, by recognizing the name *default* when looking for font and subfont file contents. Then all the hidpi scaling applies automatically. As a side effect, the concept of a 'default subfont' is gone, as are display->defaultsubfont, getdefont, and memgetdefont.