Re-add the line-continuation for cxxflag line.

systemverilog-plugin/Makefile

diff --git a/systemverilog-plugin/Makefile b/systemverilog-plugin/Makefile
index 21d0c08..b4d09ce 100644
--- a/systemverilog-plugin/Makefile
+++ b/systemverilog-plugin/Makefile
@@ -46,7 +46,7 @@
 
 CXXFLAGS += -std=c++17 -Wall -W -Wextra \
             -Wno-deprecated-declarations \
-            -Wno-unused-parameter
+            -Wno-unused-parameter \
             $(shell $(PKG_CONFIG_INVOKE) --cflags Surelog)
 
 LDFLAGS += $(shell $(PKG_CONFIG_INVOKE) --libs-only-L Surelog)