[Rd] USE_CXX1X, Snow Leopard R binaries + Mavericks

[Kevin Ushey]

Hi R-devel,

I'm noticing the following behaviour:

    writeLines("#include <Rcpp.h>", file = "test.cpp")
    Rcpp::sourceCpp("~/test.cpp") ## succeeds at trivial compile
    Sys.setenv("USE_CXX1X" = "yes")
    Rcpp::sourceCpp("~/test.cpp") ## fails; CXX nor CXX1X properly set (?)

IIUC, R is not propagating CXX nor CXX1X when USE_CXX1X is set on a
Snow Leopard CRAN build of R. Is this the expected behaviour? IIUC,
Snow Leopard binaries are built with older compilers and hence we
might not expect this to even work were CXX or CXX1X propagated (ie,
grabbing the Mavericks clang / clang++).

Comments on this in R-exts would be greatly appreciated as well.

kevinushey at s-169-232-64-218:~$ R --vanilla --slave -e "sessionInfo()"
R version 3.1.0 (2014-04-10)
Platform: x86_64-apple-darwin10.8.0 (64-bit)

locale:
[1] en_CA.UTF-8/en_CA.UTF-8/en_CA.UTF-8/C/en_CA.UTF-8/en_CA.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

kevinushey at s-169-232-64-218:~$ uname -a

Darwin s-169-232-64-218.resnet.ucla.edu 13.2.0 Darwin Kernel Version
13.2.0: Thu Apr 17 23:03:13 PDT 2014;
root:xnu-2422.100.13~1/RELEASE_X86_64 x86_64

Cheers from useR2014,
Kevin