soft16 was written as a single engine, thus it was all static/global
and had no EAPI in its functions, but then it was moved into
"src/lib/common_16" and got that, but got no prefix! That could cause
clash with other libraries, so adding such prefix.
soft8 was a copy of 16, thus had the same problems.
the engines were all based on software_x11, thus they defined the same
methods to deal with Xlib, however if you link them all in the same
binary (--enable-MODULE=static), the symbol would be redefined. Rename
symbols according to their module.
SVN revision: 52420
a22dac6ea3