Updates the cmake build system

It's still has some work, but it successfully builds on
all 3 main platforms.  Some of the outstanding items
include:

   Install target testing (mostly important for Linux)
   CMakeList clean up and comments
   Debug and Release build verification
   Audit of compile/link options
   Need a Mac signed and notarized build
   (and probably more)

locale/CMakeLists.txt

@@ -0,0 +1,174 @@
+
+set( TARGET locale )
+set( TARGET_ROOT ${topdir}/locale )
+
+message( STATUS "========== Configuring ${TARGET} ==========" )
+
+def_vars()
+
+list( APPEND SOURCES
+   af.po
+   ar.po
+   be.po
+   bg.po
+   bn.po
+   bs.po
+   ca.po
+   ca_ES@valencia.po
+   cs.po
+   cy.po
+   da.po
+   de.po
+   el.po
+   es.po
+   eu.po
+   eu_ES.po
+   fa.po
+   fi.po
+   fr.po
+   ga.po
+   gl.po
+   he.po
+   hi.po
+   hr.po
+   hu.po
+   hy.po
+   id.po
+   it.po
+   ja.po
+   ka.po
+   km.po
+   ko.po
+   lt.po
+   mk.po
+   my.po
+   nb.po
+   nl.po
+   oc.po
+   pl.po
+   pt_BR.po
+   pt_PT.po
+   ro.po
+   ru.po
+   sk.po
+   sl.po
+   sr_RS.po
+   sr_RS@latin.po
+   sv.po
+   ta.po
+   tg.po
+   tr.po
+   uk.po
+   vi.po
+   zh_CN.po
+   zh_TW.po
+)
+
+if( CMAKE_SYSTEM_NAME MATCHES "Windows" )
+
+   file( TO_NATIVE_PATH "${CMAKE_BINARY_DIR}/packages/${GETTEXT_NAME}.${GETTEXT_VERSION}/tools/bin/msgfmt.exe" msgfmt )
+
+elseif( CMAKE_SYSTEM_NAME MATCHES "Darwin" )
+   find_package( Gettext )
+   if( GETTEXT_FOUND )
+      set( msgfmt "${GETTEXT_MSGFMT_EXECUTABLE}" )
+   else()
+      set( root "${CMAKE_CURRENT_BINARY_DIR}/usr/local" )
+      set( msgfmt "${CMAKE_CURRENT_BINARY_DIR}/msgfmt" )
+
+      if( NOT EXISTS "${root}" )
+         execute_process(
+            COMMAND
+               curl -L -o /tmp/gettext.pkg https://raw.githubusercontent.com/rudix-mac/packages/master/gettext-0.20.1-macos10.14.pkg
+         )
+         execute_process(
+            COMMAND
+               pkgutil --force --expand /tmp/gettext.pkg /tmp/gettext
+         )
+         execute_process(
+            COMMAND
+               tar -C "${CMAKE_CURRENT_BINARY_DIR}" -x -f /tmp/gettext/gettextinstall.pkg/Payload
+         )
+         execute_process(
+            COMMAND
+               rm -rf /tmp/gettext.pkg /tmp/gettext 
+         )
+      endif()
+
+      file( WRITE ${CMAKE_BINARY_DIR}/msgfmt
+         "#!/bin/sh\n"
+         "export DYLD_LIBRARY_PATH=${root}/lib\n"
+         "${root}/bin/msgfmt \$@ \n"
+      )
+
+      file( COPY ${CMAKE_BINARY_DIR}/msgfmt
+         DESTINATION ${CMAKE_CURRENT_BINARY_DIR}
+         FILE_PERMISSIONS
+            OWNER_READ OWNER_EXECUTE
+            GROUP_READ GROUP_EXECUTE
+            WORLD_READ WORLD_EXECUTE
+      )
+
+      file( REMOVE ${CMAKE_BINARY_DIR}/msgfmt )
+
+   endif()
+
+ 
+else()
+
+   find_package( Gettext )
+   if( GETTEXT_FOUND )
+      set( msgfmt "${GETTEXT_MSGFMT_EXECUTABLE}" )
+   endif()
+
+endif()
+
+if( NOT DEFINED msgfmt )
+   message( WARNING "Gettext not found...translations will not be provided." )
+   return()
+endif()
+
+set( OUTPUTS )
+foreach( source ${SOURCES} )
+   get_filename_component( lang "${source}" NAME_WE )
+
+   if( CMAKE_SYSTEM_NAME MATCHES "Darwin" )
+      set( dst "${_EXEDIR}/Resources/${lang}.lproj" )
+   elseif( CMAKE_SYSTEM_NAME MATCHES "Linux" )
+      set( dst "${_EXEDIR}/locale/${lang}/LC_MESSAGES" )
+   elseif( CMAKE_SYSTEM_NAME MATCHES "Windows" )
+      set( dst "${_EXEDIR}/Languanges/${lang}" )
+   endif()
+
+   set( po "${_SRCDIR}/${source}" )
+   set( mo "${dst}/audacity.mo" )
+
+   add_custom_command(
+      DEPENDS
+         "${po}"
+      COMMAND
+         "${CMAKE_COMMAND}" -E make_directory "${dst}"
+      COMMAND
+         "${msgfmt}" -o "${mo}" "${po}"
+      OUTPUT
+         "${mo}"
+   )
+
+   # Always make sure there's an empty English folder.  Otherwise, some menu
+   # items will be translated to the next language listed in System
+   # Preferences/Language & Text
+   if( CMAKE_SYSTEM_NAME MATCHES "Darwin" )
+      add_custom_command(
+         COMMAND
+            ${CMAKE_COMMAND} -E make_directory "${_EXEDIR}/Resources/en.lproj"
+         OUTPUT
+            "${mo}"
+         APPEND
+      )
+   endif()
+
+   list( APPEND OUTPUTS ${mo} )
+endforeach()
+
+add_custom_target( "${TARGET}" ALL DEPENDS ${OUTPUTS} SOURCES "${SOURCES}" )
+