Remove flags offending CRAN

DESCRIPTION

@@ -12,6 +12,8 @@ Maintainer: Simon Garnier <[email protected]>
 Description: A simple index for estimating the degree of unimodality of a 
     multivariate empirical distribution.
 License: GPL-3
+Depends: 
+    R (>= 4.0.0)
 Imports: 
     Rcpp (>= 1.0.12),
     stats

src/Makevars

@@ -1,7 +1,7 @@
 ## With Rcpp 0.11.0 and later, we no longer need to set PKG_LIBS as there is
 ## no user-facing library. The include path to headers is already set by R.
 PKG_LIBS = $(SHLIB_OPENMP_CXXFLAGS)
-PKG_CXXFLAGS=-g -O3 $(SHLIB_OPENMP_CXXFLAGS)
+PKG_CXXFLAGS = $(SHLIB_OPENMP_CXXFLAGS)
 
 ## With R 3.1.0 or later, you can uncomment the following line to tell R to 
 ## enable compilation with C++11 (or even C++14) where available

src/Makevars.win

@@ -1,7 +1,7 @@
 ## With Rcpp 0.11.0 and later, we no longer need to set PKG_LIBS as there is
 ## no user-facing library. The include path to headers is already set by R.
 PKG_LIBS = $(SHLIB_OPENMP_CXXFLAGS)
-PKG_CXXFLAGS=-g -O3 $(SHLIB_OPENMP_CXXFLAGS)
+PKG_CXXFLAGS = $(SHLIB_OPENMP_CXXFLAGS)
 
 ## With R 3.1.0 or later, you can uncomment the following line to tell R to 
 ## enable compilation with C++11 (or even C++14) where available