Log Message:
libretro-mgba: Update to 0.8.4

0.8.4: (2020-10-29)
Emulation fixes:
 - GB Audio: Fix initial sweep state
 - GB Audio: Fix deserializing audio channels 2 and 3
 - GB Audio: Fix deserializing while audio was disabled (fixes mgba.io/i/1305)
 - GB Video: Fix drawing background when window is force-disabled by frontend
 - GB, GBA Video: Copy disable flags when drawing scanlines in proxy when not \ 
blocking
 - GBA Audio: Fix deserializing SOUNDCNT_L
 - GBA Audio: Fix stereo in XQ audio
 - GBA Audio: Fix volume/mute in XQ audio (fixes mgba.io/i/1864)
 - GBA Hardware: Fix GB Player detection on big endian platforms
 - GBA Video: Invalidate map cache when modifying BGCNT (fixes mgba.io/i/1846)
 - GBA Video: Don't draw sprites using unmapped VRAM in GL renderer (fixes \ 
mgba.io/i/1865)
 - GBA Video: Fix rare regression blending semitransparent sprites (fixes \ 
mgba.io/i/1876)
 - GBA Video: Do not affect OBJ pixel priority when writing OBJWIN (fixes \ 
mgba.io/i/1890)
 - GBA Video: Fix deferred blending when OBJWIN matches window (fixes mgba.io/i/1905)
 - GBA Video: Fix mode 4 transparency in OpenGL (fixes mgba.io/i/1907)
Other fixes:
 - ARM Decoder: Fix decoding pre-indexed writeback instructions (fixes \ 
mgba.io/i/1915)
 - Core: Fix reported ROM size when a fixed buffer size is used
 - Core: Fix memory leak loading ELF files
 - GBA: Disable more checks when loading GS save with checks disabled (fixes \ 
mgba.io/i/1851)
 - GBA: Fix endianness issues in renderer proxy
 - GBA Core: Fix memory leak when loading symbols
 - GBA Serialize: Ensure program counter is aligned when loading
Misc:
 - GBA Video: Improve speed of window texture generation on AMD