Poking around further, linker_options contains: /Users/mikekilmer/pike/build/darwin-22.6.0-x86_64/modules/Gmp/module.a
Chris says that his (Debian) install includes the -lgmp option at the end of that path. config.status contains: S["LIBS"]=" -lgmp" Makefile: MODULE_LDFLAGS=-L/usr/local/opt/ruby/lib -L/usr/local/opt/postgresql@15/lib -L/usr/local/opt/icu4c/lib \ -L/usr/local/lib -framework Foundation -framework System -framework CoreServices \ -L/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/14.0.3 \ -ldl -lutil -lm -lpoll -framework CoreServices -lgmp gmp_machine.h: #define HAVE_GMP_H 1 #define HAVE_LIBGMP 1 Mike