Ruby

transcode.c: add GC guard on raise

• transcode.c (econv_s_search_convpath): add GC guard to fix SEGV
  on raise.
  [Bug #15162] [ruby-core:89172]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64879 b2dd03c8-39d4-4d8f-98ff-823fe69b080e