Add a .desktop file, as well as a pixmap for the launcher

Makefile

@@ -2,9 +2,16 @@
 GUI_DIR   := ui
 ALSA_DIR := alsa
 
+DESTDIR ?=
+PREFIX  ?= /usr/local
+BINDIR  ?= $(DESTDIR)$(PREFIX)/bin
+
 VPATH := $(GUI_DIR):$(ALSA_DIR)
 
-INSTALLED_FILES := /usr/bin/amixer-gtk
+INSTALLED_FILES := \
+	$(BINDIR)/amixer-gtk \
+	$(DESTDIR)$(PREFIX)/share/applications/amixer-gtk.desktop \
+	$(DESTDIR)/usr/share/pixmaps/amixer-gtk.png
 
 .SUFFIXES:
 
@@ -21,7 +28,15 @@ $(WATCH_DIR)/alsa.a: $(WATCH_DEPS)
 # Essentials:
 install: $(INSTALLED_FILES)
 
-/usr/bin/amixer-gtk: $(GUI_DIR)/amixer-gtk
+$(BINDIR)/amixer-gtk: $(GUI_DIR)/amixer-gtk
+	cp $< $@
+
+$(DESTDIR)$(PREFIX)/share/applications/amixer-gtk.desktop: amixer-gtk.desktop
+	mkdir -p $(DESTDIR)$(PREFIX)/share/applications
+	cp $< $@
+
+$(DESTDIR)/usr/share/pixmaps/amixer-gtk.png: images/amixer-gtk.png
+	mkdir -p $(DESTDIR)/usr/share/pixmaps
 	cp $< $@
 
 #------- Cleaning

amixer-gtk.desktop

@@ -0,0 +1,9 @@
+[Desktop Entry]
+Name=Amixer-gtk
+Type=Application
+Exec=amixer-gtk 
+Icon=amixer-gtk
+Terminal=false
+StartupNotify=true
+Type=Application
+Categories=AudioVideo;Audio;Mixer;GTK;