Installer has hard-coded path /usr/bin/strip
On some systems, strip may not be located in /usr/bin. And even if it is, that might not be the version of strip we need to use, e.g., in a virtual hosting environment.
See, for example, this blog post about installing GHC on Dreamhost.
It seems that GHC ought to locate strip using $PATH, or some other mechanism that can be configured.