[Rd] #include_next <stdio.h> not found

[Koenker, Roger W]

Dear All,

Just when I thought I had the plague of gfortran-9 under control, I made the tactical error
of allowing my mac mini to “upgrade” to macOS 10.14.6 which apparently also upgraded
Xcode to 10.3.  In consequence I’m having difficulty building my packages.  The current
symptom is:

/usr/local/clang7/bin/clang -I"/Library/Frameworks/R.framework/Resources/include" -DNDEBUG   -I/usr/local/clang7/include/c++/v1  -fPIC  -Wall -g -O2  -c mcmb.c -o mcmb.o
In file included from mcmb.c:11:
/usr/local/clang7/include/c++/v1/stdio.h:108:15: fatal error: 'stdio.h' file not found
#include_next <stdio.h>
              ^~~~~~~~~

My first thought was I should install Simon’s clang-7.0.0 and gfortran-6.1 packages
which I dutifully did.  The next thought was to update my ~/.R/Makevars file to:

CC=/usr/local/clang7/bin/clang
CXX=/usr/local/clang7/bin/clang++
LDFLAGS=-L/usr/local/clang7/lib
CPPFLAGS=-I/usr/local/clang7/include/c++/v1
FC=/usr/local/gfortran/bin/gfortran
FLIBS=-L/usr/local/gfortran/lib -lgfortran

Further googling has left me unenlightened…  oh, and I’m running
R version 3.6.1 (2019-07-05) -- "Action of the Toes"

Roger Koenker
r.koenker using ucl.ac.uk
Department of Economics, UCL
London  WC1H 0AX.