Changing gcc optimization flag from -O0 to -Og

src/Makefile

@@ -23,7 +23,7 @@ OBJECTS += $(C_SOURCES:.c=.o)
 # appropriate rules; CXXFLAGS gets passed as part of command
 # invocation for both compilation (where -c is needed) and linking
 # (where it's not.)
-CXXFLAGS = -std=c++11 -Wall -Wextra -O0 -g -rdynamic -Wconversion
+CXXFLAGS = -std=c++11 -Wall -Wextra -Og -g -rdynamic -Wconversion
 #CXXFLAGS = -std=c++11 -Wall -Wextra -g -rdynamic
 
 CFLAGS = $(CXXFLAGS)