diff --git a/indra/cmake/00-Common.cmake b/indra/cmake/00-Common.cmake
index 6a6f7c222..0c4386784 100644
--- a/indra/cmake/00-Common.cmake
+++ b/indra/cmake/00-Common.cmake
@@ -246,44 +246,39 @@ endif (LINUX)
 
 
 if (DARWIN)
-  add_definitions(-DLL_DARWIN=1 -D_XOPEN_SOURCE)
-  set(CMAKE_CXX_LINK_FLAGS "-Wl,-headerpad_max_install_names,-search_paths_first")
+  add_definitions(-DLL_DARWIN=1)
+  set(CMAKE_CXX_LINK_FLAGS "-Wl,-no_compact_unwind -Wl,-headerpad_max_install_names,-search_paths_first")
   set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_CXX_LINK_FLAGS}")
-
-  if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mlong-branch")
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -mlong-branch")
-    # NOTE: it's critical that the optimization flag is put in front.
-    # NOTE: it's critical to have both CXX_FLAGS and C_FLAGS covered.
-    set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -O3 -msse3 -mtune=generic -mfpmath=sse ${GCC_EXTRA_OPTIMIZATIONS}")
-    set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -O3 -msse3 -mtune=generic -mfpmath=sse ${GCC_EXTRA_OPTIMIZATIONS}")
-    set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO} -O3 -msse3 -mtune=generic -mfpmath=sse ${GCC_EXTRA_OPTIMIZATIONS}")
-    set(CMAKE_C_FLAGS_RELWITHDEBINFO "${CMAKE_C_FLAGS_RELWITHDEBINFO} -O3 -msse3 -mtune=generic -mfpmath=sse ${GCC_EXTRA_OPTIMIZATIONS}")
-  elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
-    # NOTE: it's critical that the optimization flag is put in front.
-    # NOTE: it's critical to have both CXX_FLAGS and C_FLAGS covered.
-    set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -O3 -msse3")
-    set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -O3 -msse3")
-    set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO} -O3 -msse3")
-    set(CMAKE_C_FLAGS_RELWITHDEBINFO "${CMAKE_C_FLAGS_RELWITHDEBINFO} -O3 -msse3")
-  endif()
+  set(DARWIN_extra_cstar_flags "-g")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${DARWIN_extra_cstar_flags} -ftemplate-depth=256")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS}  ${DARWIN_extra_cstar_flags}")
+  # NOTE: it's critical that the optimization flag is put in front.
+  # NOTE: it's critical to have both CXX_FLAGS and C_FLAGS covered.
+  set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "-O0 ${CMAKE_CXX_FLAGS_RELWITHDEBINFO}")
+  set(CMAKE_C_FLAGS_RELWITHDEBINFO "-O0 ${CMAKE_C_FLAGS_RELWITHDEBINFO}")
+  set(CMAKE_XCODE_ATTRIBUTE_CLANG_X86_VECTOR_INSTRUCTIONS SSE3)
+  set(CMAKE_XCODE_ATTRIBUTE_GCC_OPTIMIZATION_LEVEL -O3)
+  set(CMAKE_CXX_FLAGS_RELEASE "-O3 -msse3 ${CMAKE_CXX_FLAGS_RELEASE}")
+  set(CMAKE_C_FLAGS_RELEASE "-O3 -msse3 ${CMAKE_C_FLAGS_RELEASE}")
+  if (XCODE_VERSION GREATER 4.2)
+    set(ENABLE_SIGNING TRUE)
+    set(SIGNING_IDENTITY "Developer ID Application: Linden Research, Inc.")
+  endif (XCODE_VERSION GREATER 4.2)
 endif (DARWIN)
 
 
+
 if (LINUX OR DARWIN)
+  set(GCC_WARNINGS "-Wall -Wno-sign-compare -Wno-trigraphs")
+  
   if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
     add_definitions(-DLL_GNUC=1)
-    set(UNIX_WARNINGS "-Wall -Wno-sign-compare -Wno-trigraphs")
-    set(UNIX_CXX_WARNINGS "${UNIX_WARNINGS} -Wno-reorder -Wno-non-virtual-dtor -Woverloaded-virtual")
   elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
     add_definitions(-DLL_CLANG=1)
-    set(UNIX_WARNINGS "-Wall -Wno-sign-compare -Wno-trigraphs -Wno-tautological-compare -Wno-char-subscripts -Wno-gnu -Wno-logical-op-parentheses -Wno-non-virtual-dtor")
-    set(UNIX_WARNINGS "${UNIX_WARNINGS} -Woverloaded-virtual -Wno-parentheses-equality -Wno-reorder -Wno-unused-function -Wno-unused-value -Wno-unused-variable")
-    set(UNIX_CXX_WARNINGS "${UNIX_WARNINGS}")
+    set(UNIX_WARNINGS "${UNIX_WARNINGS} -Wno-deprecated")
+    set(UNIX_CXX_WARNINGS "${UNIX_CXX_WARNINGS} -Wno-deprecated -Wno-reorder -Wno-tautological-compare")
   elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Intel")
     add_definitions(-DLL_ICC=1)
-    set(UNIX_WARNINGS "-wd327 -wd597 -wd858")
-    set(UNIX_CXX_WARNINGS "${UNIX_WARNINGS}")
   endif ()
   
   if (NOT DISABLE_FATAL_WARNINGS)
diff --git a/indra/cmake/Variables.cmake b/indra/cmake/Variables.cmake
index 5848b8934..568d29bda 100644
--- a/indra/cmake/Variables.cmake
+++ b/indra/cmake/Variables.cmake
@@ -97,24 +97,52 @@ endif (${CMAKE_SYSTEM_NAME} MATCHES "Linux")
 if (${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
   set(DARWIN 1)
 
-  if(${CMAKE_GENERATOR} MATCHES "Xcode")
-    #SDK Compiler and Deployment targets for XCode
-    if (${XCODE_VERSION} VERSION_LESS 4.0.0)
-      set(CMAKE_OSX_SYSROOT /Developer/SDKs/MacOSX10.5.sdk)
-      set(CMAKE_OSX_DEPLOYMENT_TARGET 10.5)
-    else (${XCODE_VERSION} VERSION_LESS 4.0.0)
-      set(CMAKE_OSX_SYSROOT /Developer/SDKs/MacOSX10.6.sdk)
-      set(CMAKE_OSX_DEPLOYMENT_TARGET 10.6)
-    endif (${XCODE_VERSION} VERSION_LESS 4.0.0)
-  else(${CMAKE_GENERATOR} MATCHES "Xcode")
-    set(CMAKE_OSX_SYSROOT /Developer/SDKs/MacOSX10.6.sdk)
-    set(CMAKE_OSX_DEPLOYMENT_TARGET 10.6)
-  endif(${CMAKE_GENERATOR} MATCHES "Xcode")
+  execute_process(
+    COMMAND sh -c "xcodebuild -version | grep Xcode  | cut -d ' ' -f2 | cut -d'.' -f1-2"
+    OUTPUT_VARIABLE XCODE_VERSION )
+  string(REGEX REPLACE "(\r?\n)+$" "" XCODE_VERSION "${XCODE_VERSION}")
+  
+  # To support a different SDK update these Xcode settings:
+  if (XCODE_VERSION GREATER 4.9) # (Which would be 5.0+)
+    set(CMAKE_OSX_DEPLOYMENT_TARGET 10.8)
+	set(CMAKE_OSX_SYSROOT macosx10.9)
+  else (XCODE_VERION GREATER 4.9)
+    if (XCODE_VERSION GREATER 4.5)
+        set(CMAKE_OSX_DEPLOYMENT_TARGET 10.7)
+        set(CMAKE_OSX_SYSROOT macosx10.8)
+    else (XCODE_VERSION GREATER 4.5)
+        if (XCODE_VERSION GREATER 4.2)
+          set(CMAKE_OSX_DEPLOYMENT_TARGET 10.6)
+          set(CMAKE_OSX_SYSROOT macosx10.7)
+        else (XCODE_VERSION GREATER 4.2)
+          set(CMAKE_OSX_DEPLOYMENT_TARGET 10.6)
+          set(CMAKE_OSX_SYSROOT macosx10.7)
+        endif (XCODE_VERSION GREATER 4.2)
+    endif (XCODE_VERSION GREATER 4.5)
+  endif (XCODE_VERSION GREATER 4.9)
 
-  set(CMAKE_XCODE_ATTRIBUTE_GCC_VERSION "com.apple.compilers.llvmgcc42")
+  set(CMAKE_OSX_DEPLOYMENT_TARGET 10.5)
+  set(CMAKE_OSX_SYSROOT macosx10.6)
+
+  # Support for Unix Makefiles generator
+  if (CMAKE_GENERATOR STREQUAL "Unix Makefiles")
+    execute_process(COMMAND xcodebuild -version -sdk "${CMAKE_OSX_SYSROOT}" Path | head -n 1 OUTPUT_VARIABLE CMAKE_OSX_SYSROOT)
+    string(REGEX REPLACE "(\r?\n)+$" "" CMAKE_OSX_SYSROOT "${CMAKE_OSX_SYSROOT}")
+  endif (CMAKE_GENERATOR STREQUAL "Unix Makefiles")
+      
+  # LLVM-GCC has been removed in Xcode5
+  if (XCODE_VERSION GREATER 4.9)
+    set(CMAKE_XCODE_ATTRIBUTE_GCC_VERSION "com.apple.compilers.llvm.clang.1_0")
+  else (XCODE_VERSION GREATER 4.9)
+    set(CMAKE_XCODE_ATTRIBUTE_GCC_VERSION "com.apple.compilers.llvmgcc42")
+  endif (XCODE_VERSION GREATER 4.9)
 
   set(CMAKE_XCODE_ATTRIBUTE_DEBUG_INFORMATION_FORMAT dwarf-with-dsym)
 
+  message(STATUS "Xcode version: ${XCODE_VERSION}")
+  message(STATUS "OSX sysroot: ${CMAKE_OSX_SYSROOT}")
+  message(STATUS "OSX deployment target: ${CMAKE_OSX_DEPLOYMENT_TARGET}")
+  
   # Build only for i386 by default, system default on MacOSX 10.6 is x86_64
   set(CMAKE_OSX_ARCHITECTURES i386)
   set(ARCH i386)