Improve/harmonize mobile builds

[RandomShaper]

Android:

• Inexistent DEBUG_MEMORY_ALLOC replaced by DEBUG_MEMORY_ENABLED.

iOS:

• Unconditional -fblocks. Formerly it was being added only if GameCenter enabled.
• Fix failing build if GameCenter disabled by adding GameController explicitly.
• Make release and release_debug be the same, except for DEBUG_ENABLED (for Android we are doing the same), which is: -O2 -ftree-vectorize -fomit-frame-pointer -ffast-math -funsafe-math-optimizations.
• Remove some redundant -isysroot $IPHONESDK.
• Drop the profile target.
• Enable link-time optimization (slow, but hopefully gives a faster engine).

@punto-, could you have a look?:

• I know you removed -ffast-math because of a possible compìler bug. Do you think that still applies?
• Do you know about anyone using the profile target?
• And any other possible wrong thing you find.