Copy files with `cp -pPRf` on OpenBSD.
Copy files with `cp -pPRf` on OpenBSD.

BUG=
R=dpranke@chromium.org

Review URL: https://codereview.chromium.org/1483473002 .

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