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Rterm did not always flush console output properly.
Rterm in interactive use did not implement R_FlushConsole() fully.
getGraphicsEvent did not return onMouseMove events while a mouse button was depressed.
The confirmation of a new frame for a windows() graphics device works harder to give the device focus, including bringing it to the top.
phyper(x, 0,0,0) no longer hangs for huge x and gives 1 for x >= 0. (PR#11813)
Plotmath computed the glyph metrics for the wrong character (and perhaps for a non-existent one) if this was a single-byte character with the top bit set. An example was symbol("\300").