diff --git a/src/compiler/ppc/float.lisp b/src/compiler/ppc/float.lisp
index 33e5ed05620b449144619109edabbd37b61f6652..200772f3ea81b7339aa26b9f42f452d9d8fac240 100644
--- a/src/compiler/ppc/float.lisp
+++ b/src/compiler/ppc/float.lisp
@@ -1402,7 +1402,7 @@
 (export 'get-fp-operands)
 
 (defun get-fp-operation (scp)
-  (declare (type (alien (* sigcontext)) scp))
+  (declare (type (alien (* unix:sigcontext)) scp))
   ;; Get the offending FP instruction from the context.  We return the
   ;; operation associated with the FP instruction, the precision of
   ;; the operation, and the operands of the instruction.
@@ -1440,7 +1440,7 @@
 	(values fop format rd ra rb)))))
 
 (defun get-fp-operands (scp modes)
-  (declare (type (alien (* sigcontext)) scp))
+  (declare (type (alien (* unix:sigcontext)) scp))
   ;; From the offending FP instruction, get the operation and
   ;; operands, if we can.
   (multiple-value-bind (fop format rd rs1 rs2)