fix(emacs-28): patch configure.ac to support latest libgccjit

When building Emacs 28.x the build script will attempt to patch
configure.ac if needed to support the latest version of libgccjit which
renamed libgccjit.so to libgccjit.dylib.

Fixes #72

build-emacs-for-macos

@@ -671,6 +671,17 @@ class Build
       end
     end
 
+    if effective_version == 'emacs-28'
+      p << {
+        replace: [
+          'configure.ac',
+          'grep libgccjit.so\$))"',
+          'grep -E \'libgccjit\.(so|dylib)$\'))"'
+        ],
+        allow_failure: true
+      }
+    end
+
     if effective_version == 'emacs-27'
       p << {
         url: 'https://github.com/d12frosted/homebrew-emacs-plus/raw/master/' \
@@ -720,17 +731,34 @@ class Build
       err 'Patch replace input error' unless patch[:replace].size == 3
 
       file, before, after = patch[:replace]
+      info "Applying patch to #{file}..."
       filepath = File.join(target, file)
 
-      err "\"#{file}\" does not exist in #{target}" unless File.exist?(filepath)
+      unless File.exist?(filepath)
+        if patch[:allow_failure]
+          info "File #{filepath} does not exist, skipping patch."
+          return
+        end
+
+        err "\"#{file}\" does not exist in #{target}"
+      end
 
       f = File.open(filepath, 'rb')
       s = f.read
       sub = s.gsub!(before, after)
-      err "Replacement filed in #{file}" if sub.nil?
+
+      if sub.nil?
+        if patch[:allow_failure]
+          info 'Patch did not apply, skipping.'
+          return
+        end
+
+        err "Replacement failed in #{file}"
+      end
 
       f.reopen(filepath, 'wb').write(s)
       f.close
+      info "#{file} patched."
     end
   end