For R packages using Autoconf, we'll sometimes need to be able to force the result of AC_CHECK_FUNCS.
For example, in the uuid package Autoconf sets HAVE_GETRANDOM. Despite compiling OK, using getrandom() at the time of writing fails for R packages compiled using Emscripten, due to a missing symbol. Autoconf missed this because we compile R packages with the SIDE_MODULE=1 flag. With this flag, Emscripten does not complain about the missing symbols at compile time, but the result fails at runtime.
So, using this mechanism we can force Autoconf to return "no" when checking for getrandom(), fixing the issue with uuid. We can also extend the mechanism in the future to force other AC_CHECK_FUNCS results if we find other R packages with similar runtime issues.
TODO: In the case of non-autoconf-based configure scripts we already pass extra arguments --build and --host, but in principle we should add something so that we don't pass these Autoconf flags to generic configure scripts not expecting them.
For R packages using Autoconf, we'll sometimes need to be able to force the result of
AC_CHECK_FUNCS.For example, in the
uuidpackage Autoconf setsHAVE_GETRANDOM. Despite compiling OK, usinggetrandom()at the time of writing fails for R packages compiled using Emscripten, due to a missing symbol. Autoconf missed this because we compile R packages with theSIDE_MODULE=1flag. With this flag, Emscripten does not complain about the missing symbols at compile time, but the result fails at runtime.So, using this mechanism we can force Autoconf to return "no" when checking for
getrandom(), fixing the issue withuuid. We can also extend the mechanism in the future to force otherAC_CHECK_FUNCSresults if we find other R packages with similar runtime issues.TODO: In the case of non-autoconf-based
configurescripts we already pass extra arguments--buildand--host, but in principle we should add something so that we don't pass these Autoconf flags to genericconfigurescripts not expecting them.