In the field 5x52 asm for x86_64, stack variables are provided as outputs.
The existing inputs are all forcibly allocated to registers, so cannot
coincide, but mark them as early clobber anyway to make this clearer.
Identifiers starting with an underscore and followed immediately by a capital letter are reserved by the C++ standard.
The only header guards not fixed are those in the headers auto-generated from java.
