diff --git a/master.cfg b/master.cfg
index 522ac6f..bb412e2 100644
--- a/master.cfg
+++ b/master.cfg
@@ -1301,6 +1301,15 @@ class RunTestGDBPlainSolaris_c64 (RunTestGDBSolaris_Common):
     def __init__ (self, **kwargs):
         self.extra_CFLAGS = [ '-m64' ]
         self.extra_CXXFLAGS = self.extra_CFLAGS
+        self.enable_targets_all = False
+        self.make_command = 'gmake'
+        self.run_testsuite = False
+        # While a regular gdb build succeeds, a -g -D_GLIBCXX_DEBUG
+        # build as used by the buildbot fails as reported in PR
+        # build/23676.  This can be avoided either by performing a -g
+        # -O build or with --disable-unit-tests from Sergio's proposed
+        # patch.
+        self.disable_default_compilation_flags = True
         BuildAndTestGDBFactory.__init__ (self, **kwargs)
 
 # Classes needed for ARM (running on Aarch64, on Yao's buildslave)