64-bit install path on windows was easier to fix than expected.

CMakeLists.txt

@@ -347,11 +347,17 @@ if(WIN32)
     SET(CPACK_NSIS_URL_INFO_ABOUT "http:\\\\\\\\www.openmw.org")
     SET(CPACK_NSIS_INSTALLED_ICON_NAME "omwlauncher.exe")
 
-    SET(VCREDIST "${OpenMW_BINARY_DIR}/vcredist_x86.exe")
-    if(EXISTS ${VCREDIST})
-        INSTALL(FILES ${VCREDIST} DESTINATION "redist")
+    SET(VCREDIST32 "${OpenMW_BINARY_DIR}/vcredist_x86.exe")
+    if(EXISTS ${VCREDIST32})
+        INSTALL(FILES ${VCREDIST32} DESTINATION "redist")
         SET(CPACK_NSIS_EXTRA_INSTALL_COMMANDS "ExecWait '\\\"$INSTDIR\\\\redist\\\\vcredist_x86.exe\\\" /q'" )
-    endif(EXISTS ${VCREDIST})
+    endif(EXISTS ${VCREDIST32})
+
+    SET(VCREDIST64 "${OpenMW_BINARY_DIR}/vcredist_x64.exe")
+    if(EXISTS ${VCREDIST64})
+        INSTALL(FILES ${VCREDIST64} DESTINATION "redist")
+        SET(CPACK_NSIS_EXTRA_INSTALL_COMMANDS "ExecWait '\\\"$INSTDIR\\\\redist\\\\vcredist_x64.exe\\\" /q'" )
+    endif(EXISTS ${VCREDIST64})
 
     SET(OALREDIST "${OpenMW_BINARY_DIR}/oalinst.exe")
     if(EXISTS ${OALREDIST})
@@ -360,6 +366,10 @@ if(WIN32)
             ExecWait '\\\"$INSTDIR\\\\redist\\\\oalinst.exe\\\" /s'" )
     endif(EXISTS ${OALREDIST})
 
+    if(CMAKE_CL_64)
+        SET(CPACK_NSIS_INSTALL_ROOT "$PROGRAMFILES64")
+    endif()
+
     include(CPack)
 endif(WIN32)