build: add DEBUG_LOCKCONTENTION to --enable-debug configuration

Author: jonatack

configure.ac

@@ -378,6 +378,7 @@ if test "$enable_debug" = "yes"; then
 
   AX_CHECK_PREPROC_FLAG([-DDEBUG], [DEBUG_CPPFLAGS="$DEBUG_CPPFLAGS -DDEBUG"], [], [$CXXFLAG_WERROR])
   AX_CHECK_PREPROC_FLAG([-DDEBUG_LOCKORDER], [DEBUG_CPPFLAGS="$DEBUG_CPPFLAGS -DDEBUG_LOCKORDER"], [], [$CXXFLAG_WERROR])
+  AX_CHECK_PREPROC_FLAG([-DDEBUG_LOCKCONTENTION], [DEBUG_CPPFLAGS="$DEBUG_CPPFLAGS -DDEBUG_LOCKCONTENTION"], [], [$CXXFLAG_WERROR])
   AX_CHECK_PREPROC_FLAG([-DRPC_DOC_CHECK], [DEBUG_CPPFLAGS="$DEBUG_CPPFLAGS -DRPC_DOC_CHECK"], [], [$CXXFLAG_WERROR])
   AX_CHECK_PREPROC_FLAG([-DABORT_ON_FAILED_ASSUME], [DEBUG_CPPFLAGS="$DEBUG_CPPFLAGS -DABORT_ON_FAILED_ASSUME"], [], [$CXXFLAG_WERROR])
   AX_CHECK_COMPILE_FLAG([-ftrapv], [DEBUG_CXXFLAGS="$DEBUG_CXXFLAGS -ftrapv"], [], [$CXXFLAG_WERROR])