AIX's cp command does not support -af which is the default, so use -RPf which achives something similar
AIX's cp command does not support -af which is the default, so use -RPf which achives something similar

BUG=
R=kjellander@chromium.org

Review URL: https://codereview.chromium.org/1368133002 .

Patch from David Edelsohn <dje.gcc@gmail.com>.

AWhetter/gyp,adblockplus/gyp,chromium/gyp,chromium/gyp,Phuehvk/gyp,AWhetter/gyp,turbulenz/gyp,bnoordhuis/gyp,Phuehvk/gyp,ttyangf/gyp,bnoordhuis/gyp,pandaxcl/gyp,Phuehvk/gyp,turbulenz/gyp,msc-/gyp,ttyangf/gyp,bnoordhuis/gyp,adblockplus/gyp,ttyangf/gyp,Phuehvk/gyp,pandaxcl/gyp,ttyangf/gyp,pandaxcl/gyp,msc-/gyp,pandaxcl/gyp,chromium/gyp,turbulenz/gyp,msc-/gyp,bnoordhuis/gyp,turbulenz/gyp,AWhetter/gyp,AWhetter/gyp,adblockplus/gyp,chromium/gyp,msc-/gyp,AWhetter/gyp,adblockplus/gyp,bnoordhuis/gyp,msc-/gyp,adblockplus/gyp,Phuehvk/gyp,turbulenz/gyp,ttyangf/gyp,pandaxcl/gyp,chromium/gyp