diff --git a/.hgpatchinfo/Viewer-Build.dep b/.hgpatchinfo/Viewer-Build.dep
new file mode 100644
index 0000000000..d9e1631888
--- /dev/null
+++ b/.hgpatchinfo/Viewer-Build.dep
@@ -0,0 +1 @@
+4dede9ae1ec74d41f6887719f6f1de7340d8578d
\ No newline at end of file
diff --git a/.hgpatchinfo/Viewer-Build.desc b/.hgpatchinfo/Viewer-Build.desc
new file mode 100644
index 0000000000..f784e6d741
--- /dev/null
+++ b/.hgpatchinfo/Viewer-Build.desc
@@ -0,0 +1,7 @@
+[Viewer/Build]
+- changed : compiler options for "Release with Debug" builds
+- changed : compiler and linker options for "Release" builds
+- added   : imported SNOW-788 - Fix boost lib detection with Visual Studio to allow multiple VS versions
+- changed : removed LL's changeset tags and added new (consistent) SL-2.X.Y tags for releases
+- changed : break into the debugger rather than forcing the process into an unrecoverable state for "llerrs" on non-release builds
+    -> Windows only
diff --git a/.hgtags b/.hgtags
index 8fa56c75b7..b4be156e51 100644
--- a/.hgtags
+++ b/.hgtags
@@ -3,22 +3,31 @@ bb38ff1a763738609e1b3cada6d15fa61e5e84b9 2.1.1-release
 08398e650c222336bb2b6de0cd3bba944aef11b4 2-1rn1
 0962101bfa7df0643a6e625786025fe7f8a6dc97 2-1-beta-2
 12769e547e30067d494a6c01479a18107366ce2f beta-5
+1415e6538d54fd5d568ee88343424d57c6803c2c SL-2.2.0
 17fc2908e9a1ef34a9f53a41a393caf5c3cac390 beta-3-5
 19547b909b404552593be5ec7c18241e062a6d65 2-1-1-beta-1
 1e2b517adc2ecb342cd3c865f2a6ccf82a3cf8d7 2-1-beta-3
+1ed382c6a08ba3850b6ce9061bc551ddece0ea07 SL-2.4.0
 3469d90a115b900f8f250e137bbd9b684130f5d2 beta-4
 3e4b947f79d88c385e8218cbc0731cef0e42cfc4 2-1-beta-1
 46002088d9a4489e323b8d56131c680eaa21258c viewer-2-1-0-start
+4f777ffb99fefdc6497c61385c22688ff149c659 SL-2.0.0
 4f777ffb99fefdc6497c61385c22688ff149c659 viewer-2-0-0
 52d96ad3d39be29147c5b2181b3bb46af6164f0e alpha-3
+63a6aedfce785a6c760377bf685b2dae616797d2 SL-2.5.1
 668851b2ef0f8cf8df07a0fba429e4a6c1e70abb viewer-2-0-1
+668851b2ef0f8cf8df07a0fba429e4a6c1e70abb SL-2.0.1
+6ad3d6fa35a4e320e9ce442fce2bf9c7fc852556 SL-2.3.0
 6e3b2e13906ba8ff22d3c8490b02d518adb2c907 2-1-1-beta-2
 7f16e79826d377f5f9f5b33dc721ab56d0d7dc8f alpha-4
 7f16e79826d377f5f9f5b33dc721ab56d0d7dc8f fork to viewer-20qa
 80bc6cff515118a36108967af49d3f8105c95bc9 viewer-2-0-2-start
 b03065d018b8a2e28b7de85b293a4c992cb4c12d 2-1-release
+b03065d018b8a2e28b7de85b293a4c992cb4c12d SL-2.1.0
+b723921b5c711bd24dbe77dc76ef488b544dac78 SL-2.5.0
 b8419565906e4feb434426d8d9b17dd1458e24b2 alpha-6
 bb38ff1a763738609e1b3cada6d15fa61e5e84b9 2-1-1-release
+bb38ff1a763738609e1b3cada6d15fa61e5e84b9 SL-2.1.1
 c6969fe44e58c542bfc6f1bd6c0be2fa860929ac 2-1-beta-4
 d2382d374139850efa5bb6adfb229e3e656cfc40 howard-demo
 d40ac9dd949cba6dab1cc386da6a2027690c2519 alpha-5
@@ -71,3 +80,68 @@ b723921b5c711bd24dbe77dc76ef488b544dac78 2.5.0-release
 b723921b5c711bd24dbe77dc76ef488b544dac78 DRTVWR-31_2.5.0-release
 92e58e51776a4f8c29069b1a62ff21454d2085f0 2.6.0-start
 63a6aedfce785a6c760377bf685b2dae616797d2 2.5.1-start
+0000000000000000000000000000000000000000 2.1.1-release
+0000000000000000000000000000000000000000 v2start
+0000000000000000000000000000000000000000 2-1rn1
+0000000000000000000000000000000000000000 2-1-beta-2
+0000000000000000000000000000000000000000 beta-5
+0000000000000000000000000000000000000000 beta-3-5
+0000000000000000000000000000000000000000 2-1-1-beta-1
+0000000000000000000000000000000000000000 2-1-beta-3
+0000000000000000000000000000000000000000 beta-4
+0000000000000000000000000000000000000000 2-1-beta-1
+0000000000000000000000000000000000000000 viewer-2-1-0-start
+0000000000000000000000000000000000000000 viewer-2-0-0
+0000000000000000000000000000000000000000 alpha-3
+0000000000000000000000000000000000000000 viewer-2-0-1
+0000000000000000000000000000000000000000 2-1-1-beta-2
+0000000000000000000000000000000000000000 alpha-4
+0000000000000000000000000000000000000000 fork to viewer-20qa
+0000000000000000000000000000000000000000 viewer-2-0-2-start
+0000000000000000000000000000000000000000 2-1-release
+0000000000000000000000000000000000000000 alpha-6
+0000000000000000000000000000000000000000 2-1-1-release
+0000000000000000000000000000000000000000 2-1-beta-4
+0000000000000000000000000000000000000000 howard-demo
+0000000000000000000000000000000000000000 alpha-5
+0000000000000000000000000000000000000000 fork to viewer-2-0
+0000000000000000000000000000000000000000 last_sprint
+0000000000000000000000000000000000000000 beta_2.1.3
+0000000000000000000000000000000000000000 2.2.0-beta1
+0000000000000000000000000000000000000000 2.2.0-beta2
+0000000000000000000000000000000000000000 2.2.0-beta3
+0000000000000000000000000000000000000000 2.2.0-beta4
+0000000000000000000000000000000000000000 2.3.0-beta1
+0000000000000000000000000000000000000000 2.2.0-release
+0000000000000000000000000000000000000000 2.3.0-start
+0000000000000000000000000000000000000000 2.3.0-beta1
+0000000000000000000000000000000000000000 2.3.0-beta2
+0000000000000000000000000000000000000000 2.3.0-beta3
+0000000000000000000000000000000000000000 2.3.0-release
+0000000000000000000000000000000000000000 2.4.0-start
+0000000000000000000000000000000000000000 2.4.0-beta1
+0000000000000000000000000000000000000000 2.4.0-beta1
+0000000000000000000000000000000000000000 2.4.0-beta2
+0000000000000000000000000000000000000000 2.4.0-release
+0000000000000000000000000000000000000000 2.5.0-start
+0000000000000000000000000000000000000000 2.5.0-beta1
+0000000000000000000000000000000000000000 2.5.0-beta2
+0000000000000000000000000000000000000000 DRTVWR-5_2.2.0-beta1
+0000000000000000000000000000000000000000 DRTVWR-3_2.2.0-beta2
+0000000000000000000000000000000000000000 DRTVWR-7_2.2.0-beta3
+0000000000000000000000000000000000000000 DRTVWR-8_2.2.0-release
+0000000000000000000000000000000000000000 DRTVWR-14_2.3.0-beta1
+0000000000000000000000000000000000000000 DRTVWR-17_2.3.0-beta2
+0000000000000000000000000000000000000000 DRTVWR-20_2.3.0-beta3
+0000000000000000000000000000000000000000 DRTVWR-13_2.3.0-release
+0000000000000000000000000000000000000000 DRTVWR-26_2.4.0-beta1
+0000000000000000000000000000000000000000 DRTVWR-27_2.4.0-beta2
+0000000000000000000000000000000000000000 DRTVWR-25_2.4.0-release
+0000000000000000000000000000000000000000 DRTVWR-32_2.5.0-beta1
+0000000000000000000000000000000000000000 DRTVWR-33_2.5.0-beta2
+0000000000000000000000000000000000000000 2.5.0-beta3
+0000000000000000000000000000000000000000 DRTVWR-34_2.5.0-beta3
+0000000000000000000000000000000000000000 2.5.0-release
+0000000000000000000000000000000000000000 DRTVWR-31_2.5.0-release
+0000000000000000000000000000000000000000 2.6.0-start
+0000000000000000000000000000000000000000 2.5.1-start
diff --git a/indra/cmake/00-Common.cmake b/indra/cmake/00-Common.cmake
index dbe0cf5cd0..5d0027c6d0 100644
--- a/indra/cmake/00-Common.cmake
+++ b/indra/cmake/00-Common.cmake
@@ -39,10 +39,10 @@ if (WINDOWS)
   set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} /Od /Zi /MDd /MP"
       CACHE STRING "C++ compiler debug options" FORCE)
   set(CMAKE_CXX_FLAGS_RELWITHDEBINFO 
-      "${CMAKE_CXX_FLAGS_RELWITHDEBINFO} /Od /Zi /MD /MP /Ob2"
+      "${CMAKE_CXX_FLAGS_RELWITHDEBINFO} /Od /Zi /MD /Ob2 /Gm"
       CACHE STRING "C++ compiler release-with-debug options" FORCE)
   set(CMAKE_CXX_FLAGS_RELEASE
-      "${CMAKE_CXX_FLAGS_RELEASE} ${LL_CXX_FLAGS} /O2 /Zi /MD /MP /Ob2"
+      "${CMAKE_CXX_FLAGS_RELEASE} ${LL_CXX_FLAGS} /O2 /Zi /MD /Ob2 /Oi /Ot /GF /Gy /arch:SSE2"
       CACHE STRING "C++ compiler release options" FORCE)
 
   set(CMAKE_CXX_STANDARD_LIBRARIES "")
@@ -79,6 +79,20 @@ if (WINDOWS)
   # configure win32 API for windows XP+ compatibility
   set(WINVER "0x0501" CACHE STRING "Win32 API Target version (see http://msdn.microsoft.com/en-us/library/aa383745%28v=VS.85%29.aspx)")
   add_definitions("/DWINVER=${WINVER}" "/D_WIN32_WINNT=${WINVER}")
+    
+  # Various libs are compiler specific, generate some variables here we can just use
+  # when we require them instead of reimplementing the test each time.
+  if (MSVC71)
+	set(MSVC_DIR 7.1)
+	set(MSVC_SUFFIX 71)
+  elseif (MSVC80)
+	set(MSVC_DIR 8.0)
+	set(MSVC_SUFFIX 80)
+  elseif (MSVC90)
+	set(MSVC_DIR 9.0)
+	set(MSVC_SUFFIX 90)
+  endif (MSVC71)
+  
 endif (WINDOWS)
 
 
diff --git a/indra/cmake/Boost.cmake b/indra/cmake/Boost.cmake
index 7ce57a5572..dcbc801663 100644
--- a/indra/cmake/Boost.cmake
+++ b/indra/cmake/Boost.cmake
@@ -16,27 +16,30 @@ else (STANDALONE)
 
   if (WINDOWS)
     set(BOOST_VERSION 1_39)
-    if (MSVC71)
-      set(BOOST_PROGRAM_OPTIONS_LIBRARY 
-          optimized libboost_program_options-vc71-mt-s-${BOOST_VERSION}
-          debug libboost_program_options-vc71-mt-sgd-${BOOST_VERSION})
-      set(BOOST_REGEX_LIBRARY
-          optimized libboost_regex-vc71-mt-s-${BOOST_VERSION}
-          debug libboost_regex-vc71-mt-sgd-${BOOST_VERSION})
-      set(BOOST_SIGNALS_LIBRARY 
-          optimized libboost_signals-vc71-mt-s-${BOOST_VERSION}
-          debug libboost_signals-vc71-mt-sgd-${BOOST_VERSION})
-    else (MSVC71)
-      set(BOOST_PROGRAM_OPTIONS_LIBRARY 
-          optimized libboost_program_options-vc80-mt-${BOOST_VERSION}
-          debug libboost_program_options-vc80-mt-gd-${BOOST_VERSION})
-      set(BOOST_REGEX_LIBRARY
-          optimized libboost_regex-vc80-mt-${BOOST_VERSION}
-          debug libboost_regex-vc80-mt-gd-${BOOST_VERSION})
-      set(BOOST_SIGNALS_LIBRARY 
-          optimized libboost_signals-vc80-mt-${BOOST_VERSION}
-          debug libboost_signals-vc80-mt-gd-${BOOST_VERSION})
-    endif (MSVC71)
+   
+	# SNOW-788
+	# 00-Common.cmake alreay sets MSVC_SUFFIX to be correct for the VS we are using eg VC71, VC80, VC90 etc
+	# The precompiled boost libs for VC71 use a different suffix to VS80 and VS90
+	# This code should ensure the cmake rules are valid for any VS being used in future as long as the approprate
+	# boost libs are avaiable - RC.
+	
+	if (MSVC71)
+	    set(BOOST_OPTIM_SUFFIX mt-s)
+	    set(BOOST_DEBUG_SUFFIX mt-sgd)
+	else (MSVC71)
+	    set(BOOST_OPTIM_SUFFIX mt)
+	    set(BOOST_DEBUG_SUFFIX mt-gd)
+	endif (MSVC71)
+		
+    set(BOOST_PROGRAM_OPTIONS_LIBRARY 
+          optimized libboost_program_options-vc${MSVC_SUFFIX}-${BOOST_OPTIM_SUFFIX}-${BOOST_VERSION}
+          debug libboost_program_options-vc${MSVC_SUFFIX}-${BOOST_DEBUG_SUFFIX}-${BOOST_VERSION})
+    set(BOOST_REGEX_LIBRARY
+          optimized libboost_regex-vc${MSVC_SUFFIX}-${BOOST_OPTIM_SUFFIX}-${BOOST_VERSION}
+          debug libboost_regex-vc${MSVC_SUFFIX}-${BOOST_DEBUG_SUFFIX}-${BOOST_VERSION})
+    set(BOOST_SIGNALS_LIBRARY 
+          optimized libboost_signals-vc${MSVC_SUFFIX}-${BOOST_OPTIM_SUFFIX}-${BOOST_VERSION}
+          debug libboost_signals-vc${MSVC_SUFFIX}-${BOOST_DEBUG_SUFFIX}-${BOOST_VERSION})
   elseif (DARWIN)
     set(BOOST_PROGRAM_OPTIONS_LIBRARY boost_program_options-xgcc40-mt)
     set(BOOST_REGEX_LIBRARY boost_regex-xgcc40-mt)
diff --git a/indra/newview/CMakeLists.txt b/indra/newview/CMakeLists.txt
index af6beacdfa..83a636420e 100644
--- a/indra/newview/CMakeLists.txt
+++ b/indra/newview/CMakeLists.txt
@@ -1436,7 +1436,7 @@ if (WINDOWS)
     if(MSVC71)
         set(release_flags "/MAP:Release/${VIEWER_BINARY_NAME}.map /MAPINFO:LINES")
     else(MSVC71)
-        set(release_flags "/MAP:Release/${VIEWER_BINARY_NAME}.map")
+        set(release_flags "/MAP:Release/${VIEWER_BINARY_NAME}.map /OPT:REF")
     endif(MSVC71)
     
     set_target_properties(${VIEWER_BINARY_NAME}
diff --git a/indra/newview/llappviewer.cpp b/indra/newview/llappviewer.cpp
index a23f809b71..c0410f69b3 100644
--- a/indra/newview/llappviewer.cpp
+++ b/indra/newview/llappviewer.cpp
@@ -1846,7 +1846,14 @@ void errorCallback(const std::string &error_string)
 	//Set the ErrorActivated global so we know to create a marker file
 	gLLErrorActivated = true;
 	
+//	LLError::crashAndLoop(error_string);
+// [SL:KB] - Patch: Viewer-Build | Checked: 2010-12-04 (Catznip-2.5.0a) | Added: Catznip-2.4.0g
+#if !LL_RELEASE_FOR_DOWNLOAD && LL_WINDOWS
+	DebugBreak();
+#else
 	LLError::crashAndLoop(error_string);
+#endif // LL_RELEASE_WITH_DEBUG_INFO && LL_WINDOWS
+// [/SL:KB]
 }
 
 bool LLAppViewer::initLogging()