Test failure on ppc64 (big endian)

Important Information

Provide following Information:

• mpv version: 0.35.0
• Linux Distribution and Version: Gentoo (rolling)
• Source of the mpv binary: Gentoo ebuild
• If known which version of mpv introduced the problem: N/A
• Window Manager and version: N/A
• GPU driver and version: N/A
• Possible screenshot or video of visual glitches: N/A

Reproduction steps

1. Try to run the test suite on PPC64 (big endian)
2. Observe failure

I'm wondering if it's an issue in the tests rather than an actual failure because of the +/- with [le] and [be], but I'm not familiar enough with mpv to be sure. Access to the test environment is possible if required.

Expected behavior

All tests pass.

Actual behavior

Some tests fail resulting in SIGABRT.

Log file

Log: http://sprunge.us/tmUEyT or https://bugs.gentoo.org/attachment.cgi?id=845213

Snippet:

[...]
-yuva444p9be: [GENERIC] ctype=uint
-  Basic desc: [ba][bb][a][yuvp][yuv][be][uint]
+yuva444p9le: [GENERIC] ctype=uint
+  Basic desc: [ba][bb][a][yuvp][yuv][le][uint]
     planes=4, chroma=0:0 align=1:1
     {16/[0:0] 16/[0:0] 16/[0:0] 16/[0:0] }
     0: 16bits endian_bytes=2 {0:16/-7} {} {} {}
     1: 16bits endian_bytes=2 {} {0:16/-7} {} {}
     2: 16bits endian_bytes=2 {} {} {0:16/-7} {}
     3: 16bits endian_bytes=2 {} {} {} {0:16/-7}
-  AVD: name=yuva444p9be chroma=0:0 flags=0x91 [be][planar][alpha]
+  AVD: name=yuva444p9le chroma=0:0 flags=0x90 [planar][alpha]
     0: p=0  st=2  o=0  sh=0  d=9
     1: p=1  st=2  o=0  sh=0  d=9
     2: p=2  st=2  o=0  sh=0  d=9
     3: p=3  st=2  o=0  sh=0  d=9
 yuva444pf: ctype=float
-  Basic desc: [ba][bb][a][yuv][le][float]
+  Basic desc: [ba][bb][a][yuv][be][float]
     planes=4, chroma=0:0 align=1:1
     {32/[0:0] 32/[0:0] 32/[0:0] 32/[0:0] }
     0: 32bits {0:32} {} {} {}
[cplayer] Giving up.
/var/tmp/portage/media-video/mpv-0.35.0-r1/temp/environment: line 1952:    31 Aborted                 (core dumped) "$@"
 * ERROR: media-video/mpv-0.35.0-r1::gentoo failed (test phase):
 *   Failed to run command: /var/tmp/portage/media-video/mpv-0.35.0-r1/work/mpv-0.35.0-build/mpv --no-config -v --unittest=all-simple

Start by running mpv --no-config -v --unittest=all-simple on a PPC64 big-endian environment and compare the failing output with the reported log. Focus on the endian-related test results and SIGABRT; done means the test suite completes successfully with all tests passing.