-nostdinc
Do not search the standard system directories for header files. Only the directories explicitly specified with -I, -iquote, -isystem, and/or -idirafter options (and the directory of the current file, if appropriate) are searched.
-nostdinc++
Do not search for header files in the C++-specific standard directories, but do still search the other standard directories. (This option is used when building the C++ library.)
From Dealing with Catalina and Dealing with Catalina II, we need to modify how the compiler is setup to ease the C++ exception issue.
@bgoodri seems to have found a good option here:
Note, the
-nostdinc++
is disabling standard directorys, c.f. https://gcc.gnu.org/onlinedocs/gcc/Directory-Options.html