2.1.6 doesn't work on MacOS (wheee...)

Rakefile

@@ -103,10 +103,10 @@ task 'gem:native' do
   if RUBY_PLATFORM =~ /darwin/
     FileUtils.touch 'grpc_c.32.ruby'
     FileUtils.touch 'grpc_c.64.ruby'
-    system "rake cross native gem RUBY_CC_VERSION=2.3.0:2.2.2:2.1.6:2.0.0 V=#{verbose}"
+    system "rake cross native gem RUBY_CC_VERSION=2.3.0:2.2.2:2.1.5:2.0.0 V=#{verbose}"
   else
     Rake::Task['dlls'].execute
-    docker_for_windows "bundle && rake cross native gem RUBY_CC_VERSION=2.3.0:2.2.2:2.1.6:2.0.0 V=#{verbose}"
+    docker_for_windows "bundle && rake cross native gem RUBY_CC_VERSION=2.3.0:2.2.2:2.1.5:2.0.0 V=#{verbose}"
   end
 end
 

third_party/rake-compiler-dock/Dockerfile

@@ -107,9 +107,9 @@ RUN bash -c "rvm use 2.3.0 --default && \
     rake-compiler cross-ruby VERSION=2.2.2 HOST=i686-w64-mingw32 && \
     rake-compiler cross-ruby VERSION=2.2.2 HOST=x86_64-w64-mingw32 && \
     rake-compiler cross-ruby VERSION=2.2.2 HOST=x86_64-linux-gnu && \
-    rake-compiler cross-ruby VERSION=2.1.6 HOST=i686-w64-mingw32 && \
+    rake-compiler cross-ruby VERSION=2.1.5 HOST=i686-w64-mingw32 && \
-    rake-compiler cross-ruby VERSION=2.1.6 HOST=x86_64-w64-mingw32 && \
+    rake-compiler cross-ruby VERSION=2.1.5 HOST=x86_64-w64-mingw32 && \
-    rake-compiler cross-ruby VERSION=2.1.6 HOST=x86_64-linux-gnu && \
+    rake-compiler cross-ruby VERSION=2.1.5 HOST=x86_64-linux-gnu && \
     rake-compiler cross-ruby VERSION=2.0.0-p645 HOST=i686-w64-mingw32 && \
     rake-compiler cross-ruby VERSION=2.0.0-p645 HOST=x86_64-w64-mingw32 && \
     rake-compiler cross-ruby VERSION=2.0.0-p645 HOST=x86_64-linux-gnu && \
@@ -120,7 +120,7 @@ RUN bash -c "rvm use 2.3.0 --default && \
     export MAKE=\"make -j`nproc`\" CFLAGS='-m32 -s -O1 -fno-omit-frame-pointer -fno-fast-math' LDFLAGS='-m32' && \
     rake-compiler cross-ruby VERSION=2.3.0 HOST=i686-linux-gnu && \
     rake-compiler cross-ruby VERSION=2.2.2 HOST=i686-linux-gnu && \
-    rake-compiler cross-ruby VERSION=2.1.6 HOST=i686-linux-gnu && \
+    rake-compiler cross-ruby VERSION=2.1.5 HOST=i686-linux-gnu && \
     rake-compiler cross-ruby VERSION=2.0.0-p645 HOST=i686-linux-gnu && \
     rm -rf ~/.rake-compiler/tmp/builds ~/.rake-compiler/sources && \
     find /usr/local/rvm -type d -print0 | sudo xargs -0 chmod g+sw "
@@ -164,6 +164,6 @@ RUN cp /tmp/build/runas /usr/local/bin/
 # Install sudoers configuration
 RUN cp /tmp/build/sudoers /etc/sudoers.d/rake-compiler-dock
 
-ENV RUBY_CC_VERSION 2.3.0:2.2.2:2.1.6:2.0.0
+ENV RUBY_CC_VERSION 2.3.0:2.2.2:2.1.5:2.0.0
 
 CMD bash

tools/distrib/build_ruby_environment_macos.sh

@@ -51,7 +51,7 @@ EOF
 
 MAKE="make -j8"
 
-for v in 2.3.0 2.2.2 2.1.6 2.0.0-p645 ; do
+for v in 2.3.0 2.2.2 2.1.5 2.0.0-p645 ; do
   rake -f $CROSS_RUBY cross-ruby VERSION=$v HOST=x86_64-darwin11
 done