Makefile: fixes and parallel by default

This commit:
- fixes the OpenGL lib configurations (gl->epoxy)
- added an exclusion for bin/ and build/ in .gitignore
- make the Makefile parallel

.gitignore

@@ -0,0 +1,2 @@
+bin/*
+build/*

Makefile

@@ -2,11 +2,12 @@
 .DELETE_ON_ERROR: $(BINDIR)/Getting_Started_with_GTK
 .DEFAULT_GOAL: all
 
-NTHREADS= $(shell nproc)
+CPUS ?= $(shell (nproc --all || sysctl -n hw.ncpu) 2>/dev/null || echo 1)
+MAKEFLAGS += --jobs=$(CPUS)
 
 CC=gcc
-CFLAGS=`pkg-config --cflags gtk4 gl glib-2.0 libxml-2.0`
-LDFLAGS=`pkg-config --libs gtk4 gl glib-2.0 libxml-2.0` -lGL -lGLU -lm -lepoxy -lX11 -lGLEW
+CFLAGS=`pkg-config --cflags gtk4 epoxy glib-2.0 libxml-2.0`
+LDFLAGS=`pkg-config --libs gtk4 epoxy glib-2.0 libxml-2.0` -lGL -lGLU -lm -lepoxy -lX11 -lGLEW
 WARNINGS = -Wall
 DEBUG = -ggdb -fno-omit-frame-pointer #-fdiagnostics-color=always -fsanitize=bounds -fstack-check
 OPTIMIZE = -O3
@@ -27,10 +28,12 @@ all: $(BINDIR)/gem-graph-client
 # Directories
 #
 $(BUILDDIR):
-	mkdir -p $@
+	@mkdir -p $@
+	@echo "    MKDIR $@"
 
 $(BINDIR):
-	mkdir -p $@
+	@mkdir -p $@
+	@echo "    MKDIR $@"
 
 #
 # Dependencies
@@ -38,34 +41,39 @@ $(BINDIR):
 -include $(DEPENDENCIES)
 
 $(BUILDDIR)/%.d: %.c Makefile | $(BUILDDIR)
-	mkdir -p $(shell dirname $@)
-	$(CC) $(CFLAGS) -MM -MT $(@:%.d=%.o) -MF $@ $<
+	@mkdir -p $(shell dirname $@)
+	@$(CC) $(CFLAGS) -MM -MT $(@:%.d=%.o) -MF $@ $<
+	@echo "    DEP $@"
 
 #
 # Main program
 #
 $(BINDIR)/gem-graph-client: $(OBJECTS) | $(BINDIR)
-	$(CC) $(LDFLAGS) $(WARNINGS) $(DEBUG) $(OPTIMIZE) $^ -o $@
+	@$(CC) $(LDFLAGS) $(WARNINGS) $(DEBUG) $(OPTIMIZE) $^ -o $@
+	@echo "    LD $@"
 
 #
 # Objects
 #
 $(BUILDDIR)/%.o: %.c Makefile | $(BUILDDIR)
-	mkdir -p $(shell dirname $@)
-	$(CC) $(CFLAGS) $(WARNINGS) $(DEBUG) $(OPTIMIZE) -c $< -o $@
+	@mkdir -p $(shell dirname $@)
+	@$(CC) $(CFLAGS) $(WARNINGS) $(DEBUG) $(OPTIMIZE) -c $< -o $@
+	@echo "    CC $@"
 
 #
 # Virtual recipes
 #
 install:
-	echo "Installing is not supported"
+	@echo "Installing is not supported"
 
 run: $(BINDIR)/gem-graph-client
 	$(BINDIR)/gem-graph-client
 
 clean:
-	rm -rf $(BINDIR)
-	rm -rf $(BUILDDIR)
+	@rm -rf $(BINDIR)
+	@echo "    RM $(BINDIR)"
+	@rm -rf $(BUILDDIR)
+	@echo "    RM $(BUILDDIR)"
 
 
 # More docs :