vfs-relix:  Constify argv/envp in relix_entry
Genie:  Constify argv/envp in Process::Run()
relix:  Constify memory_data::get_{argv,envp}()
Merge branch 'constify-argv'
plus:  Add class argv

The plus::argv class encapsulates the details of storing string data and
an array of pointers for use with exec functions expecting char* arrays.
It can be used for the envp parameter to execve() as well as argv.
relix:  Use plus::argv
Merge branches 'argv' and 'execve' into vfork-child-env
httpd:  Don't pass server environment to CGI code
httpd:  Avoid mods to vfork child's environment
libc:  Add execvpe()

This is nonstandard, but it exists in glibc and QNX, at least.
Merge branch 'execvpe' into vfork-child-env
sh:  Avoid modifying environment during vfork

Duplicate execvpe() for OS X, which doesn't have it.
Merge branches 'httpd-env' and 'sh-env' into vfork-child-env
Merge branch 'vfork-child-env'