Respond to PR comments

clean up usage of vcs.mk
Bump hammer and plugins for updated API

vcs.mk

@@ -3,8 +3,10 @@ PERMISSIVE_OFF=+permissive-off
 
 WAVEFORM_FLAG=+vcdplusfile=$(sim_out_name).vpd
 
+CLOCK_PERIOD ?= 1.0
+RESET_DELAY ?= 777.7
+
 VCS_CC_OPTS = \
-	-CC "-I$(VCS_HOME)/include" \
 	-CC "-I$(RISCV)/include" \
 	-CC "-std=c++11"
 
@@ -21,12 +23,14 @@ VCS_NONCC_OPTS = \
 	+vc+list \
 	-f $(sim_common_files) \
 	-sverilog \
+	-debug_pp \
 	+incdir+$(build_dir) \
 	$(sim_vsrcs) \
 	+libext+.v
 
 VCS_DEFINE_OPTS = \
-	+define+CLOCK_PERIOD=1.0 \
+	+define+CLOCK_PERIOD=$(CLOCK_PERIOD) \
+	+define+RESET_DELAY=$(RESET_DELAY) \
 	+define+PRINTF_COND=$(TB).printf_cond \
 	+define+STOP_COND=!$(TB).reset \
 	+define+RANDOMIZE_MEM_INIT \