Bump to v6.0.0-rc4+dev42

Part of IC:Caelum+dev4, nasa/cFS#432

**Includes**

PR #1215
- Resolve UT uninitialized variable warnings

PR #1219
- Add ut_assert to doxygen and fix warnings

PR #1223
- Protect if OS_FDGetInfo called on socket

README.md

@@ -11,6 +11,13 @@ The autogenerated OSAL user's guide can be viewed at <https://github.com/nasa/cF
 
 ## Version History
 
+### Development Build: v6.0.0-rc4+dev42
+
+- Resolve UT uninitialized variable warnings
+- Add ut_assert to doxygen and fix warnings
+- Protect if OS_FDGetInfo called on socket
+- See <https://github.com/nasa/osal/pull/1226> and <https://github.com/nasa/cFS/pull/432>
+
 ### Development Build: v6.0.0-rc4+dev32
 
 - Typesafe definition of osal_id_t

src/os/inc/osapi-version.h

@@ -36,7 +36,7 @@
 /*
  * Development Build Macro Definitions
  */
-#define OS_BUILD_NUMBER   32
+#define OS_BUILD_NUMBER   42
 #define OS_BUILD_BASELINE "v6.0.0-rc4"
 
 /*