diff --git a/.gitignore b/.gitignore
index 60ab6f4..6eab03e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,4 @@
 *~
-build/
 test*
 obj/
+hexview
diff --git a/Makefile b/Makefile
index f927adb..811ab2a 100644
--- a/Makefile
+++ b/Makefile
@@ -1,8 +1,12 @@
 SRC=$(wildcard src/*.cpp)
 INCLUDE =include
-CXXFLAGS = -Wall -pedantic --std=gnu++20 $(addprefix -I,$(INCLUDE))
-CXXFLAGS+= -flto -felide-constructors -fgraphite -O3
-LDFLAGS = -lfmt -O3 -flto 
+_HX_FEAT?= -DFIXED_ROW_SIZE=24
+
+CXXFLAGS?= -pipe -O3 -march=native
+CXXFLAGS+= -flto -felide-constructors -fgraphite 
+CXXFLAGS+= -Wall -pedantic --std=gnu++20 $(addprefix -I,$(INCLUDE))
+LDFLAGS?= -O3 -flto
+LDFLAGS+= -lfmt
 
 PROJ = hexview
 
@@ -15,7 +19,7 @@ dirs:
 	@mkdir -p obj/src
 
 obj/%.o: %.cpp
-	$(CXX) -c $< $(CXXFLAGS) -o $@ $(LDFLAGS)
+	$(CXX) -c $< $(_HX_FEAT) $(CXXFLAGS) -o $@ $(LDFLAGS)
 
 $(PROJ): $(OBJ)
 	$(CXX) $^ $(CXXFLAGS) -o $@ $(LDFLAGS)
diff --git a/src/hex.cpp b/src/hex.cpp
index 9a52363..7cdded2 100644
--- a/src/hex.cpp
+++ b/src/hex.cpp
@@ -25,7 +25,7 @@ const static constexpr char ascii_map[256] = {
 #endif
 
 #ifdef FIXED_ROW_SIZE
-constexpr int ROW_SZ = FIXED_ROW_SIZE;
+constexpr const int ROW_SZ = FIXED_ROW_SIZE;
 #endif
 
 namespace hv {