add -DARMA_NO_DEBUG

[vandenman]

To test, save the code below in src/russian_roulette.cpp

#include <RcppArmadillo.h>

// [[Rcpp::export]]
double bigbomb(const arma::mat& v, const int i) {
  return v(i);
}

and build. Note that with this PR, you should see -DARMA_NO_DEBUG in the build panel of RStudio. Next, in R do

v <- t(c(1, 2, 3))
bgms:::bigbomb(v, 10000000)

and then RStudio will show the notorious bomb before restarting.

To revert, open Makevars.in and change

-PKG_CPPFLAGS = @RCPP_PARALLEL_CPPFLAGS@ -DARMA_NO_DEBUG
+PKG_CPPFLAGS = @RCPP_PARALLEL_CPPFLAGS@ #-DARMA_NO_DEBUG

build once more, and then the R code shows:

> bgms:::bigbomb(v, 10000000)
Error: Mat::operator(): index out of bounds