anchor.diff:  cd R-devel-strict    # important to change directory name before building not after because the path is baked into the build, iiuc
   # Following R-exts#4.3.3
   
  -./configure --without-recommended-packages --disable-byte-compiled-packages --disable-openmp --enable-strict-barrier CC="gcc -fsanitize=undefined,address -fno-sanitize=float-divide-by-zero -fno-omit-frame-pointer" CFLAGS="-O0 -g -Wall -pedantic" LIBS="-lpthread"
  +./configure --without-recommended-packages --disable-byte-compiled-packages --disable-openmp --enable-strict-barrier --disable-long-double CC="gcc -fsanitize=undefined,address -fno-sanitize=float-divide-by-zero -fno-omit-frame-pointer"
  +# CFLAGS an LIBS seem to be ignored now by latest R-devel/gcc, and it works without : CFLAGS="-O0 -g -Wall -pedantic" LIBS="-lpthread"
  +# Adding --disable-long-double (see R-exts) in the same configure as ASAN/UBSAN used to fail, but now works. So now noLD is included in this strict build.
  +# Other flags used in the past: CC="gcc -std=gnu99" CFLAGS="-O0 -g -Wall -pedantic -ffloat-store -fexcess-precision=standard"
   # For ubsan, disabled openmp otherwise gcc fails in R's distance.c:256 error: ‘*.Lubsan_data0’ not specified in enclosing parallel
   # UBSAN gives direct line number under gcc but not clang it seems. clang-5.0 has been helpful too, though.
   # If use later gcc-8, add F77=gfortran-8
  
positive.code: 
  cd ..
  R
  cc(clean=TRUE)  # to compile with -pedandic. Also use very latest gcc (currently gcc-7) as CRAN does
  saf = options()$stringsAsFactors
  options(stringsAsFactors=!saf)    # check tests (that might be run by user) are insensitive to option, #2718
  test.data.table()
  
negative.code: #############################################################################
  There are some things to overcome to achieve compile without USE_RINTERNALS, though.
  
  
  ########################################################################
  #  rchk : https://github.com/kalibera/rchk
  