Fixed GEM & PyPI packages to use SDK from Xcode when building the extension

Author: bentoi

ice/gem/extconf.rb

@@ -5,6 +5,7 @@
 # **********************************************************************
 
 require "mkmf"
+require "rbconfig"
 
 if RUBY_PLATFORM =~ /mswin|mingw/
     puts "MinGW is not supported with Ice for Ruby."
@@ -32,6 +33,9 @@
 #
 if RUBY_PLATFORM =~ /darwin/
     $ARCH_FLAG = "-arch x86_64"
+    # Make sure to use the SDK from Xcode (required for Sierra where old system headers can be used otherwise)
+    RbConfig::MAKEFILE_CONFIG['CC'] = 'xcrun -sdk macosx clang'
+    RbConfig::MAKEFILE_CONFIG['CXX'] = 'xcrun -sdk macosx clang++'
 end
 
 $INCFLAGS << ' -Iice/cpp/include'

ice/pypi/setup.py

@@ -60,6 +60,9 @@
 if platform == 'darwin':
     if not 'ARCHFLAGS' in os.environ:
         os.environ['ARCHFLAGS'] = '-arch x86_64'
+    # Make sure to use the SDK from Xcode (required for Sierra where old system headers can be used otherwise)
+    os.environ['CC'] = 'xcrun -sdk macosx clang'
+    os.environ['CXX'] = 'xcrun -sdk macosx clang++'
     extra_compile_args.append('-w')
     if use_ice:
         libraries = ["IceSSL", "IceLocatorDiscovery", "IceDiscovery", "Ice"]