diff --git a/master.cfg b/master.cfg
index 7818499..90dd9a0 100644
--- a/master.cfg
+++ b/master.cfg
@@ -1212,7 +1212,7 @@ class RunTestGDBNativeExtendedGDBServer_c32t32 (BuildAndTestGDBFactory):
 class RunTestGDBIndexBuild (BuildAndTestGDBFactory):
     """Testing with the "cc-with-tweaks.sh" passing -i."""
     def __init__ (self, **kwargs):
-        self.extra_make_check_flags = [ util.Interpolate ('RUNTESTFLAGS=CC_FOR_TARGET="/bin/sh %(prop:builddir)s/binutils-gdb/gdb/contrib/cc-with-tweaks.sh -i gcc" CXX_FOR_TARGET="/bin/sh %(prop:builddir)s/binutils-gdb/gdb/contrib/cc-with-tweaks.sh -i g++"') ]
+        self.test_env = { "RUNTESTFLAGS" : util.Interpolate ('CC_FOR_TARGET="/bin/sh %(prop:builddir)s/binutils-gdb/gdb/contrib/cc-with-tweaks.sh -i gcc" CXX_FOR_TARGET="/bin/sh %(prop:builddir)s/binutils-gdb/gdb/contrib/cc-with-tweaks.sh -i g++') }
         BuildAndTestGDBFactory.__init__ (self, **kwargs)
 
 class RunTestGDBIndexBuild_c32t32 (BuildAndTestGDBFactory):