Merge remote-tracking branch 'ripple/develop' into develop

Builds/CMake/RippledCore.cmake

@@ -157,7 +157,9 @@ install (
     src/ripple/basics/MathUtilities.h
     src/ripple/basics/safe_cast.h
     src/ripple/basics/Slice.h
+    src/ripple/basics/spinlock.h
     src/ripple/basics/StringUtilities.h
+    src/ripple/basics/ThreadSafetyAnalysis.h
     src/ripple/basics/ToString.h
     src/ripple/basics/UnorderedContainers.h
     src/ripple/basics/XRPAmount.h

Builds/CMake/RippledDocs.cmake

@@ -31,7 +31,7 @@ if (tests)
     # find_path sets a CACHE variable, so don't try using a "local" variable.
     find_path (${variable} "${name}" ${ARGN})
     if (NOT ${variable})
-      message (WARNING "could not find ${name}")
+      message (NOTICE "could not find ${name}")
     else ()
       message (STATUS "found ${name}: ${${variable}}/${name}")
     endif ()