cmake: drop the waffle library prefix on Windows
cmake: drop the waffle library prefix on Windows

Be a bit more consistent with Windows, rather than other platforms and
drop the library prefix. Suggested by Jose.

v2: Rebase

Signed-off-by: Emil Velikov <4c996f2f093ddd0585a556460b4cc3ba555546ef@gmail.com>

maurossi/waffle,fjhenigman/waffle,fjhenigman/waffle,dcbaker/waffle,waffle-gl/waffle,evelikov/waffle,dcbaker/waffle,waffle-gl/waffle,evelikov/waffle,dcbaker/waffle,maurossi/waffle,maurossi/waffle,fjhenigman/waffle,chadversary/waffle,chadversary/waffle,waffle-gl/waffle,evelikov/waffle,chadversary/waffle,waffle-gl/waffle