if (.Platform$OS.type == "windows") {
    if (!is.null(.Platform$r_arch) && .Platform$r_arch == "x64") {
        stop(paste("OpenMx is not yet supported on 64-bit R for Windows.",
             "Please use 32-bit R in the interim."), call. = FALSE)
    }
    repos <- c('http://openmx.psyc.virginia.edu/testing/')
    install.packages(pkgs=c('OpenMx'), repos=repos)
} else {
    if (Sys.info()["sysname"] == "Darwin") {
        darwinVers <- as.numeric(substr(Sys.info()['release'], 1, 2))
        if (darwinVers > 10) {
            msg <- paste("We have detected that you are running on OS X 10.7 or greater",
		"whose native version of gcc does not support the OpenMP API.", 
		"As a result your default installation has been set to single-threaded.",
		"If you have installed the mac ports version of gcc to address this issue",
		"please choose the multi-threaded installation option.")
    	    msg <- gsub('(.{1,80})(\\s|$)', '\\1\n', msg)
            cat(msg)
            cat("1. single-threaded [default]\n")
            cat("2. multi-threaded \n")
            select <- readline("Which version of OpenMx should I install? ")

            if (select == "") {
                select <- 1
     	    } 

        } else {
            cat("1. single-threaded\n")
            cat("2. multi-threaded [default]\n")
            select <- readline("Which version of OpenMx should I install? ")

            if (select == "") {
                select <- 2
	    }
        }
    } else {
        cat("1. single-threaded\n")
        cat("2. multi-threaded [default]\n")
        select <- readline("Which version of OpenMx should I install? ")

        if (select == "") {
            select <- 2
        }
    }

    if (!(select %in% c(1,2))) {
        stop("Please enter '1' or '2'", call. = FALSE)
    }
  
    if (select == 1) {
        repos <- c('http://openmx.psyc.virginia.edu/testing-sequential/')
        install.packages(pkgs=c('OpenMx'), repos=repos, 
  	           configure.args=c('--disable-openmp'))
    } else if (select == 2) {
        repos <- c('http://openmx.psyc.virginia.edu/testing/')
        install.packages(pkgs=c('OpenMx'), repos=repos)
    } else {
        stop(paste("Unknown installation type", select))
    }
}