Catalin,

Quick question: IIRC, earlier aarch64 gcc versions did not generate
__ILP32__ when -mabi=ilp32, they only removed __LP64__. When did the
change happen? Could we assume that all compiler versions used to
generate ILP32 would define this?

The __ILP32__ define has been supported since 

commit b01b37f5768911598640cf8a8c82beacb4200c13
Author: yufeng <yufeng@138bc75d-0d04-0410-961f-82ee72b054a4>
Date:   Tue Jul 23 12:26:33 2013 +0000

    [AArch64, ILP32] 4/6 Define _ILP32 and __ILP32__.
    
    gcc/
    
        * config/aarch64/aarch64.h (TARGET_CPU_CPP_BUILTINS): Define _ILP32
        and __ILP32__ when the ILP32 model is in use.
    
    
    git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk at 201167 138bc75d-0d04-0410-961f-82ee72b054a4

Best regards,
Philipp.