Found the following significant warnings:
  inner.cpp:100:15: warning: anonymous non-C-compatible type given name for linkage purposes by typedef declaration; add a tag name here [-Wnon-c-typedef-for-linkage]
  inner.cpp:312:15: warning: anonymous non-C-compatible type given name for linkage purposes by typedef declaration; add a tag name here [-Wnon-c-typedef-for-linkage]
  inner.cpp:411:15: warning: anonymous non-C-compatible type given name for linkage purposes by typedef declaration; add a tag name here [-Wnon-c-typedef-for-linkage]
  ./npde.h:29:15: warning: anonymous non-C-compatible type given name for linkage purposes by typedef declaration; add a tag name here [-Wnon-c-typedef-for-linkage]
  init.c:57:27: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  init.c:144:24: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  /home/hornik/tmp/R.check/r-devel-clang/Work/build/Packages/rxode2/include/rxode2.h:51:30: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  /home/hornik/tmp/R.check/r-devel-clang/Work/build/Packages/rxode2/include/rxode2.h:304:33: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  /home/hornik/tmp/R.check/r-devel-clang/Work/build/Packages/rxode2/include/rxode2.h:306:30: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  /home/hornik/tmp/R.check/r-devel-clang/Work/build/Packages/rxode2/include/rxode2.h:308:22: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  /home/hornik/tmp/R.check/r-devel-clang/Work/build/Packages/rxode2/include/rxode2.h:309:23: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  /home/hornik/tmp/R.check/r-devel-clang/Work/build/Packages/rxode2/include/rxode2.h:317:19: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
See '/home/hornik/tmp/R.check/r-devel-clang/Work/PKGS/nlmixr2est.Rcheck/00install.out' for details.