RFR: 8262366: Update glib to version 2.66.7

[Kevin Rushforth]

On Thu, 1 Apr 2021 08:07:56 GMT, Johan Vos <jvos at openjdk.org> wrote:

>> I cannot reproduce build failure on Linux.
>
> It compiles for me (on gcc-9, 10.1 and 10.2) but I can imagine it doesn't compile on all configurations. `memset` is declared in `string.h` and that may or may not be included. 
> Running gcc -H shows that on my system, `string.h` is included by `glib-2.0/glib/gtestutils.h` (which is included by `glib-2.0/glib.h`) but on other systems, that might not be the case.
> Since this PR introduces `memset` in the `audio-buffer.c` file, I think it is safest to include `string.h` in this file as well, as this removes the dependency on that file to be included indirectly.

Alexander tried it on our CI build machine yesterday and it builds fine there, too. I should add that I was building on a very old Ubuntu 16.04 system.

> Since this PR introduces memset in the audio-buffer.c file, I think it is safest to include string.h in this file as well, as this removes the dependency on that file to be included indirectly.

I was thinking the same thing. There is one more file that should include `<string.h>`: `qtdemux_tags.c` uses `strlen`and fails to compile on my system. With the change to include `string.h` in those two files, the build now passes on my system.

-------------

PR: https://git.openjdk.java.net/jfx/pull/447