Patch 2 of 2:
See the attached `0002_treat-impossible-line-size-as-zero.patch`.

Current Gnash's implementation `MovieClip.lineStyle()` treats line thickness
of `Infinity` as 255, while Flash Player treats it (together as other
impossible line size like negative number, and NaN) as 0.

This patch adds a special-case check to `MovieClip.lineStyle()` which
explicitly set the line size to zero (hairline stroke) when `Infinity`,
`-Infinity` or `NaN` line size value is encountered.

Automated tests will follow as a separate patch entry.

Note:

• In original code, behavior of `NaN` line size is correct but it depends on order of comparison used inside `clamp()` function. Explicit `NaN` check is added to ensure correct behavior regardless of how `clamp()` was implemented.
• I'm not sure why `clamp()` function was used as `<float>` rather than `<double>` despite `toNumber()` returning `double` and `pixelsToTwips()` accepting `double` argument. I left this part intact as nearby code seems to do similar thing.

Gnash: 0.8.11dev (patched against git 051aa9c 15-Feb-2016)
System: Debian GNU/Linux 7.0 Wheezy i386


(file #36380)

Current Gnash's implementation of `MovieClip.lineStyle()` has an incorrect
handling of `thickness` argument when it have special value like
`undefined` or `Infinity`, a.k.a. bug #45731.

Patch 1 of 2:
See the attached `0001_reset-line-style-on-undefined-stroke.patch`.

Original code of `MovieCLip.lineStyle()` implementation already resets
line style when the method was called without any argument, but it doesn't
reset line style when `thickness` argument is specified as `undefined`,
and left it to number conversion code's interpretation, which results
in hairline (width 0) stroke.

This patch extends the condition check to cover the case where
`thickness` argument is specified, but as `undefined`, which has
essentially the same meaning; partially fixing bug #45731.

Gnash: 0.8.11dev (patched against git 02ec1e6 3-Feb-2016)
System: Debian GNU/Linux 7.0 Wheezy i386