[Rd] RODBC on Mac & _R_CHECK_FORCE_SUGGESTS_

[Spencer Graves]

        "R CMD check sos" with R 3.3.0 under Mac OS X 10.11.5 ends as 
follows:


  >* checking package dependencies ... ERROR
  >Package suggested but not available: ‘RODBC’
  >
  >The suggested packages are required for a complete check.
  >Checking can be attempted without them by setting the environment
  >variable _R_CHECK_FORCE_SUGGESTS_ to a false value.


        Unfortunately, "install.packages('RODBC')" says it's only 
available in source form.  When I  attempt to install from sources, it 
fails as follows:


  >checking for sqlext.h... no
  >configure: error: "ODBC headers sql.h and sqlext.h not found"
  >ERROR: configuration failed for package ‘RODBC’
  >* removing 
‘/Library/Frameworks/R.framework/Versions/3.3/Resources/library/RODBC’
  >Warning in install.packages :
  >  installation of package ‘RODBC’ had non-zero exit status


        The CRAN checks for RODBC also failed for the same reason 
(https://cloud.r-project.org/web/checks/check_results_RODBC.html).



        I'm not sure how to set "the environment variable 
_R_CHECK_FORCE_SUGGESTS_ to a false value" on my Mac, and I'd rather not 
do it permanently.  I tried various versions of "R CMD check 
_R_CHECK_FORCE_SUGGESTS_=FALSE sos_1.3-9.tar.gz" and "R CMD check 
_R_CHECK_FORCE_SUGGESTS_=0 sos_1.3-9.tar.gz", none of which worked. 
Somewhere I found a suggestion to try, "R CMD check --as-cran 
sos_1.3-9.tar.gz".  That also failed for me.


        Suggestions?
        Thanks,
        Spencer Graves