SERVER-26845 Fix compile with clang-3.9

(cherry picked from commit b0885dbb66f94332a3cf8ab5bf2565b70cd59384)

1 files changed, 6 insertions, 0 deletions

diff --git a/SConstruct b/SConstruct
index e64a03bb2da..7eb1536dc6e 100644
--- a/SConstruct
+++ b/SConstruct
@@ -1812,6 +1812,12 @@ def doConfigure(myenv):
         # see: http://stackoverflow.com/questions/21755206/how-to-get-around-gcc-void-b-4-may-be-used-uninitialized-in-this-funct
         AddToCXXFLAGSIfSupported(myenv, "-Wno-maybe-uninitialized")
 
+        # Disable warning about templates that can't be implicitly instantiated. It is an attempt to
+        # make a link error into an easier-to-debug compiler failure, but it triggers false
+        # positives if explicit instantiation is used in a TU that can see the full definition. This
+        # is a problem at least for the S2 headers.
+        AddToCXXFLAGSIfSupported(myenv, "-Wno-undefined-var-template")
+
     # Check if we need to disable null-conversion warnings
     if myenv.ToolchainIs('clang'):
         def CheckNullConversion(context):