ticket:10184 Remove cplusplus ifdefs from umutex.h

git-svn-id: http://source.icu-project.org/repos/icu/icu@34027 251d0590-4201-4cf1-90de-194747b24ca1
ticket:10184 Remove cplusplus ifdefs from umutex.h

git-svn-id: http://source.icu-project.org/repos/icu/icu@34028 251d0590-4201-4cf1-90de-194747b24ca1
ticket:10184 umutex.h, change to C++ only, in preparation for build time user mutex support.

git-svn-id: http://source.icu-project.org/repos/icu/icu@34029 251d0590-4201-4cf1-90de-194747b24ca1
ticket:10281: Temporary patch for MST problem in locale en_MO. Next CLDR data sync should resolve the issue in a different way.

git-svn-id: http://source.icu-project.org/repos/icu/icu@34030 251d0590-4201-4cf1-90de-194747b24ca1