Fix build on i386 with clang.
Some inline asm requires 7 registers but only 6 are available because
clang assumes the stack is 4-byte aligned and there's a local variable
that requires 16-byte alignment so the stack has to be realigned which
requires one register to be used as frame pointer.
Submitted by: firstname.lastname@example.org
Approved by: Thomas Zander <email@example.com> (maintainer)