Merge pull request #190 from applandinc/xcode13_20210928

fix: Fix compilation on macOS with Xcode 13

Author: apotterri

ext/appmap/extconf.rb

@@ -1,6 +1,17 @@
 require "mkmf"
 
+
 $CFLAGS='-Werror'
+
+# Per https://bugs.ruby-lang.org/issues/17865,
+# compound-token-split-by-macro was added in clang 12 and broke
+# compilation with some of the ruby headers. If the current compiler
+# supports the new warning, turn it off.
+new_warning = '-Wno-error=compound-token-split-by-macro'
+if try_cflags(new_warning)
+  $CFLAGS += ' ' + new_warning
+end
+
 extension_name = "appmap"
 dir_config(extension_name)
 create_makefile(File.join(extension_name, extension_name))