There is no need to compile our DLLs as shared libraries since we are
managing symbols exports and imports through spec files.
On my system, this reduces the configure-time by a factor of two.
ReactOS/Windows headers contain lots of structures whose last field is
fieldName[ANYSIZE] or fieldName[1].
Starting with GCC 4.8, gcc considers that accessing items [2], [3], ...
are undefined operation, and may optimize those accesses by removing them!
Add flag -fno-aggressive-loop-optimizations to prevent this unwanted behaviour.