LIBRETRO: BUILD: fix emscripten build #7

Job	Run time
Windows (win32, x86-windows, x86, --enable-discord --enable-faad --enable-gif --enable-mikmod --e...	32m 53s
Windows (arm64, arm64, arm64-windows, --enable-discord --enable-faad --enable-gif --enable-mikmod...	27m 10s
Windows (x64, x64, x64-windows, --enable-discord --enable-faad --enable-gif --enable-mikmod --ena...	31m 49s
Xcode (ios7, -scheme ScummVM-iOS CODE_SIGN_IDENTITY="" CODE_SIGNING_ALLOWED=NO, --use-xcframework...	5m 56s
Emscripten (emscripten, --enable-gif --enable-jpeg --enable-ogg --enable-png --enable-vorbis --en...	40m 42s
Emscripten (emscripten (extra libs), --enable-gif --enable-jpeg --enable-ogg --enable-png --enabl...	28m 46s
Xcode (macosx, -scheme ScummVM-macOS -destination 'platform=macOS,arch=x86_64', --disable-nasm --...	5m 48s
Ubuntu (ubuntu-22.04, sdl-config, ccache g++-4.8, g++-4.8 liba52-dev libcurl4-openssl-dev libfaad...	3m 6s
Ubuntu (ubuntu-latest, sdl2-config, ccache g++, liba52-dev libcurl4-openssl-dev libfaad-dev libfl...	4m 35s
	3h 0m 45s

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