Attempting to build the perf tool for an arm64 target results in the
following failure:
  arch/arm64/util/unwind-libunwind.c: In function 'libunwind__arch_reg_id':
  arch/arm64/util/unwind-libunwind.c:77:3: error: implicit declaration of function 'pr_err'
     pr_err("unwind: invalid reg id %d\n", regnum);
     ^
  arch/arm64/util/unwind-libunwind.c:77:3: error: nested extern declaration of 'pr_err'
This is due to commit 
		
	
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|---|---|---|
| .. | ||
| arm | ||
| arm64 | ||
| powerpc | ||
| s390 | ||
| sh | ||
| sparc | ||
| x86 | ||
| common.c | ||
| common.h | ||