This area has been subsumed into tests for LLVM pre-17 shown at
https://www.stats.ox.ac.uk/pub/bdr/clang17/ and as 'Additional issues' on the 
CRAN results pages.

------------------------

Tests of instaling packages using 'flang-new' as the Fortran compiler and
clang for C/C++, on x86_64 Linux.

'flang-new' is an under-development Fortran 2018 compiler whose sources are
part of LLVM and is an optional part of the build.  Binary distributions of
LLVM are avaiable from 

https://github.com/llvm/llvm-project/releases

which may contain flang -- the Windows builds are incompatible with the
toolchain used to build R.

Currently using LLVM trunk which reports as 17.0.0.

The principal inteest in this compiler is that it allows R to be built for 
Windows on ARM.  So we have been exploring which packages can currently be
installed using the compiler on a more readily available platform.

derfc is obsolete: use erfc
dlgama is a GNU extension: the F2008 function is LOG_GAMMA.
etime is a GNU extension which  can be replaced by CPU_TIME and/or
SYSTEM_CLOCK.
getpid is a GNU extension.
int8 should be INT(,KIND=8)
isnan is a GNU extension.  There are standard ways to do this as from F2003,
or you can use if(my_var /= my_var).

htdp rapidly reached 60GB of VM when compilation was attempted
and had to be terminated.