Build

Merge pull request #881 from tmyqlfpir/fix-save #977

Job	Run time
Windows MSYS2 x86_64 GCC	10m 50s
Windows MSYS2 i686 GCC	10m 22s
Windows MSYS2 x86_64 GCC without SDL	9m 44s
Linux GCC	4m 48s
Linux GCC SDL 1.2	3m 58s
Linux Clang	6m 18s
Linux Clang without GL	5m 32s
Linux Clang without Polymer	6m 11s
macOS Clang	3m 8s
	1h 0m 51s

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