Windows shm stuff is in the 1.5.x branch via r1534011

git-svn-id: https://svn.apache.org/repos/asf/apr/apr/trunk@1534865 13f79535-47bb-0310-9956-ffa450edef68
clang scan-build noted that we sometimes assigned garbage
to the mutex field, since the conditions under which we 
got the mutex vs. accessed it were different; simplify


git-svn-id: https://svn.apache.org/repos/asf/apr/apr/trunk@1534873 13f79535-47bb-0310-9956-ffa450edef68