I can't claim to understand this, but on my system of same age, using system clang, configure does complete. It does get that error on line 23748, but that, and several similar subsequent tests just end up returning "yes".
configure:23748: checking for size_t configure:23748: gcc -arch x86_64 -c -g -O2 -I/usr/local/include conftest.c >&5 configure:23748: $? = 0 configure:23748: gcc -arch x86_64 -c -g -O2 -I/usr/local/include conftest.c >&5 conftest.c:118:21: error: expected expression if (sizeof ((size_t))) ^ 1 error generated. [..snip..] configure:23748: result: yes (as usual, configure code is nigh on unreadable, but I think the logic is that the size_t type exists if you can do "sizeof (size_t)", but not "sizeof ((size_t))", so the error is expected.) The line that trips you up comes later: configure:24611: checking size of size_t configure:24616: gcc -arch x86_64 -o conftest -g -O2 -I/usr/local/include -L/usr/ local/lib conftest.c -ldl -lm >&5 configure:24616: $? = 0 configure:24616: ./conftest configure:24616: $? = 0 configure:24630: result: 8 so that is where you should look for clues (or at least tell us what it says there). -pd > On 18 Aug 2019, at 13:34 , Göran Broström <goran.brost...@umu.se> wrote: > > Hello, > > I'm (for the first time) trying to build R-devel from source (to be able to > check my CRAN packages on a Mac), but it breaks already after > > gobr0002@MBP-2:~/R/src/R-devel$ ./configure > > with > > checking size of size_t... configure: error: in `/Users/gb/R/src/R-devel': > configure: error: cannot compute sizeof (size_t) > See `config.log' for more details > > Some 'details' regarding size_t: > > configure:23748: checking for size_t > configure:23748: gcc -c -g -O2 -I/usr/local/include conftest.c >&5 > configure:23748: $? = 0 > configure:23748: gcc -c -g -O2 -I/usr/local/include conftest.c >&5 > conftest.c: In function 'main': > conftest.c:116:21: error: expected expression before ')' token > if (sizeof ((size_t))) > ^ > > My MacBook Pro is old (2010), so I am stuck with MacOS 10.13.6, XCode 10.1. > I'm using clang 7.0.0 and fortran 6.1.0. > > Do I need to buy a new Mac? > > Thanks, Göran > > _______________________________________________ > R-SIG-Mac mailing list > R-SIG-Mac@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-mac -- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Office: A 4.23 Email: pd....@cbs.dk Priv: pda...@gmail.com _______________________________________________ R-SIG-Mac mailing list R-SIG-Mac@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-mac