Issue
I encountered ffi gem build error while running bundle install
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.
current directory: /Users/toshimaru/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/ffi-1.14.2/ext/ffi_c
/Users/toshimaru/.rbenv/versions/2.7.1/bin/ruby -I /Users/toshimaru/.rbenv/versions/2.7.1/lib/ruby/2.7.0 -r
./siteconf20201228-73606-f28m46.rb extconf.rb
checking for ffi_prep_closure_loc() in -lffi... yes
checking for ffi_prep_cif_var()... yes
checking for ffi_raw_call()... yes
checking for ffi_prep_raw_closure()... yes
creating extconf.h
creating Makefile
current directory: /Users/toshimaru/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/ffi-1.14.2/ext/ffi_c
make "DESTDIR=" clean
current directory: /Users/toshimaru/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/ffi-1.14.2/ext/ffi_c
make "DESTDIR="
compiling AbstractMemory.c
compiling ArrayType.c
compiling Buffer.c
compiling Call.c
compiling ClosurePool.c
compiling DynamicLibrary.c
compiling Function.c
Function.c:847:17: error: implicit declaration of function 'ffi_prep_closure_loc' is invalid in C99
[-Werror,-Wimplicit-function-declaration]
ffiStatus = ffi_prep_closure_loc(closure->pcl, &fnInfo->ffi_cif, callback_invoke, closure, code);
^
Function.c:847:17: note: did you mean 'ffi_prep_closure'?
/Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/usr/include/ffi/ffi.h:269:1: note: 'ffi_prep_closure' declared here
ffi_prep_closure(
^
1 error generated.
make: *** [Function.o] Error 1
make failed, exit code 2
Gem files will remain installed in /Users/toshimaru/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/ffi-1.14.2 for
inspection.
Results logged to
/Users/toshimaru/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/extensions/x86_64-darwin-18/2.7.0/ffi-1.14.2/gem_make.out
An error occurred while installing ffi (1.14.2), and Bundler cannot continue.
Make sure that `gem install ffi -v '1.14.2' --source 'https://rubygems.org/'` succeeds before bundling.
In Gemfile:
bootstrap-sass was resolved to 3.4.1, which depends on
sassc was resolved to 2.4.0, which depends on
ffi
Solution
Install ffi with opttion --disable-system-libffi.
$ gem install ffi -- --disable-system-libffi
# x.x.x is version
$ gem install ffi:x.x.x -- --disable-system-libffi