EMI: Enable alpha blending for global alpha values of actors

This fixes the problem, that all actors with a global alpha
value < 1.0f were not drawn with the correct transparency.
MYST3: Properly reset the movie scripts
GRIM: SHADERS: Remove f literal suffix

Some Android shader compiler do not like it apparently
Merge pull request #1096 from chkr-private/alpha-fixes

EMI: Enable alpha blending for global alpha values of actors
AMIGAOS4: corrected cross building
AMIGAOS4: use upper case for target
GRIM/EMI: workaround for compilation error
MACOSX: added libiconv static lib
TINYGL: gl -> tgl rename
AMIGAOS4: replace package lha to zip