Adds desktop file and updates makefile and readme to reflect changes

Makefile

@@ -23,11 +23,13 @@ else
 	@echo Skipping upx compression
 endif
 
-.PHONY: install
-install: build compress
+.PHONY: install-bin
+install-bin: build compress
 	install -d ${DESTDIR}${BINDIR}
 	install -m 0755 ./${BINARY} ${DESTDIR}${BINDIR}
 
+.PHONY: install
+install: install-bin install-desktop clean
 
 .PHONY: clean
 	${GOCMD} clean
@@ -35,3 +37,16 @@ install: build compress
 .PHONY: uninstall
 uninstall: clean
 	rm -f ${DESTDIR}${BINDIR}/${BINARY}
+	rm -f ${DESTDIR}${DATAROOTDIR}/applications/${BINARY}
+	rm -f ${DESTDIR}${DATAROOTDIR}/pixmaps/${BINARY}-icon.png
+	-update-desktop-database 2> /dev/null
+
+.PHONY: install-desktop
+install-desktop: ${BINARY}-icon.png
+ifeq ($(shell uname), Linux)
+	install -d ${DESTDIR}${DATAROOTDIR}/applications
+	install -m 0644 ./${BINARY}.desktop ${DESTDIR}${DATAROOTDIR}/applications
+	install -d ${DESTDIR}${DATAROOTDIR}/pixmaps
+	install -m 0644 ./${BINARY}-icon.png ${DESTDIR}${DATAROOTDIR}/pixmaps
+	-update-desktop-database 2> /dev/null
+endif

README.md

@@ -25,7 +25,7 @@ Most of the keys can be figured out if you don't know what they are already. I w
 
 ## Building
 
-Minor build variations can be found for each system. Using upx (`apt install upx` or `brew install upx`) will reduce binary size by a good bit for any of these systems. After running the build command, and optionally running upx, move the resulting binary onto your path and you are good to go. Makefile coming soon<sup>TM</sup>.
+Minor build variations can be found for each system. Using upx (`apt install upx` or `brew install upx`) will reduce binary size by a good bit for any of these systems. After running the build command, and optionally running upx, move the resulting binary onto your path and you are good to go.
 
 ### OSX / Linux
 
@@ -35,7 +35,7 @@ Alternatively, you can just run a few things yourself and avoid make altogether:
 
 `go build -ldflags "-s -w" -o gnums && upx gnums`
 
-You would then need to move the executable to where you want it.
+You would then need to move the executable to where you want it, as well as install the desktop entry/icon (linux only).
 
 ### Windows
 

gnums.desktop

@@ -0,0 +1,10 @@
+[Desktop Entry]
+Type=Application
+Name=gnums
+GenericName=RPN Calculator
+Comment=Reverse Polish Notation Calculator
+Terminal=false
+Categories=Utility;Calculator;
+Exec=gnums
+Icon=gnums-icon
+