How to install on 10.15 with deployment target as 10.13?

[Ken Cunningham]

> Hi, I'm compiling postgres with LLVM support on macOS 10.15 Catalina. The binaries are supported on 10.13+. On target machine (10.13), the library fails to load with the following error: *dlopen(/Library/PostgreSQL/13/lib/postgresql/llvmjit.so, 10): Symbol not found: ____chkstk_darwin* 

I believe you will have to compile your software built on 10.15 and to be deployed on earlier systems with:

configure.cflags-append -fno-stack-check
configure.cxxflags-append -fno-stack-check

to disable the now-default stack-checking feature used in Xcode 11.

The  ____chkstk_darwin symbol is not found on 10.13 it appears, and although there are versions of that symbol added to compiler_rt for other systems like WIndows, etc, it is apparently expected to be found in the system libraries on Darwin.

Ken