gistfile1.py

diff --git a/python/lsst/sconsUtils/dependencies.py b/python/lsst/sconsUtils/dependencies.py
index 98d89cd..d837e1d 100644
--- a/python/lsst/sconsUtils/dependencies.py
+++ b/python/lsst/sconsUtils/dependencies.py
@@ -72,10 +72,11 @@ def configure(packageName, versionString=None, eupsProduct=None, eupsProductPath
     # XCPPPATH is a new variable defined by sconsUtils - it's like CPPPATH, but the headers
     # found there aren't treated as dependencies.  This can make scons a lot faster.
     state.env['XCPPPATH'] = []
+    state.env['XCPPPREFIX'] = "-isystem "
     state.env['_CPPINCFLAGS'] = \
         "$( ${_concat(INCPREFIX, CPPPATH, INCSUFFIX, __env__, RDirs, TARGET, SOURCE)}"\
-        " ${_concat(INCPREFIX, XCPPPATH, INCSUFFIX, __env__, RDirs, TARGET, SOURCE)} $)"
-    state.env['_SWIGINCFLAGS'] = state.env['_CPPINCFLAGS'].replace("CPPPATH", "SWIGPATH")
+        " ${_concat(XCPPPREFIX, XCPPPATH, INCSUFFIX, __env__, RDirs, TARGET, SOURCE)} $)"
+    state.env['_SWIGINCFLAGS'] = state.env['_CPPINCFLAGS'].replace("CPPPATH", "SWIGPATH").replace("XCPPPREFIX", "SWIGINCPREFIX")
 
     if state.env.linkFarmDir:
         for d in [state.env.linkFarmDir, "#"]:

Does this work for all compilers? I see that clang, icc, and g++ at least 4.4+ support this so maybe we don't need to check (those are the compilers that sconsUtils currently knows about)

I've only checked clang and g++. There was some discussion on HipChat as to what compiler support was required, but no particular conclusion.

The above was a quick & dirty hack; if we were to adopt something like this, we could presumably concoct something to check if the compiler supports it. I didn't get a feeling of great support when I first mooted the idea, so I've not spent any longer thinking about it (although I think there were only a couple of folks awake when I raised it, so maybe others feel differently).