Makefile.in: refactor install rules

This refactor aims to reduce the amount of duplicated Bash code that is
used in all of the distribution packages (AUR, COPR, and Nixpkgs).

* Introduce install-linux and install-darwin targets, which are
  automatically selected by make where appropriate.
    * install-linux installs icons and the CraftOS-PC.desktop file.
    * install-darwin installs CraftOS-PC.app to /Applications.
* Introduce install-bin, install-headers, and install-liblua targets, which install the
  respective components.
* Introduce fixup-liblua-path target, which uses patchelf to change the
  name of liblua.so (appears to be common across all packages).
* Introduce target for resources/linux-icons.zip.
* Remove the DESTDIR variable, instead using Autoconf's install
  directories feature [1]
* Introduce the INSTALL_TARGETS variable, which is used to control what
  dependencies the install rule has.
* Introduce the EXTRA_PLATFORM_INSTALL_TARGETS variable, which is
  conditionally set depending on the platform.
* Introduce the LIBLUA_NAME variable, which is used to control what file
  patchelf changes liblua.so from.

This refactor **does not** include code to install craftos2-rom, since
that appears to be out-of-scope.

[1]: https://www.gnu.org/software/autoconf/manual/autoconf-2.63/html_node/Installation-Directory-Variables.html

Author: tomodachi94

Makefile.in

@@ -8,8 +8,16 @@ LDFLAGS=@LDFLAGS@
 LIBEXT=.so
 ifndef OS
 ifeq (@OUT_TARGET@, craftos)
+ifeq ($(shell uname), Linux)
+EXTRA_PLATFORM_INSTALL_TARGETS=install-linux fixup-liblua-path
+endif
+endif
+endif
+ifndef OS
+ifeq (@OUT_TARGET@, craftos)
 ifeq ($(shell uname), Darwin)
 LIBEXT=.dylib
+EXTRA_PLATFORM_INSTALL_TARGETS=install-darwin
 endif
 endif
 endif
@@ -22,11 +30,20 @@ LIBEXT=.dylib
 endif
 endif
 endif
+INSTALL_TARGETS?=install-bin install-headers install-liblua $(EXTRA_PLATFORM_INSTALL_TARGETS)
 PREFIX?=@prefix@
 prefix=$(PREFIX)
-DESTDIR?=@exec_prefix@
+ifdef DESTDIR
+$(error "The DESTDIR variable was removed. Please set PREFIX if you would like to change where everything will be installed, or set BINDIR if you would like to change where binaries will be installed.")
+endif
+BINDIR=@bindir@
+SHAREDIR=@datarootdir@
+INCLUDEDIR=@includedir@
+LIBDIR=@libdir@
+MACAPPDIR=$(PREFIX)/Applications
+LIBLUA_NAME=libcraftos2-liblua
 ifneq (/usr,$(PREFIX))
-CPPFLAGS:=$(CPPFLAGS) -DCUSTOM_ROM_DIR=\"$(PREFIX)/share/craftos\"
+CPPFLAGS:=$(CPPFLAGS) -DCUSTOM_ROM_DIR=\"$(SHAREDIR)/craftos\"
 endif
 SDIR=@srcdir@/src
 IDIR=@srcdir@/api
@@ -127,6 +144,9 @@ $(ODIR)/apis_%_handle.o: $(SDIR)/apis/handles/%_handle.cpp $(SDIR)/apis/handles/
 	echo " [CXX]   $@"
 	$(CXX) -o $@ -c $(CPPFLAGS) $(CXXFLAGS) $(CFLAGS) $<
 
+resources/linux-icons: resources/linux-icons.zip
+	unzip resources/linux-icons.zip -d resources/linux-icons
+
 mac-plugin:
 	echo " [LD]    ccemux.bundle"
 	$(CXX) -std=c++17 -bundle -fpic -o ccemux.bundle examples/ccemux.cpp craftos2-lua/src/liblua$(LIBEXT) -lSDL2 -Icraftos2-lua/include -Iapi
@@ -137,20 +157,63 @@ linux-plugin:
 
 clean: $(ODIR)
 	rm -f craftos
+	rm -rf resources/linux-icons
 	find obj -type f -not -name speaker_sounds.o -exec rm -f {} \;
 
 rebuild: clean craftos
 
-install: craftos
-	echo " [CP]    $(DESTDIR)/craftos"
-	cp craftos $(DESTDIR)/craftos
+fixup-liblua-path: craftos
+	echo " [FIXUP] craftos"
+	patchelf --replace-needed craftos2-lua/src/liblua.so "$(LIBLUA_NAME)$(LIBEXT)" ./craftos
+
+install-darwin: macapp
+	cp -r CraftOS-PC.app $(MACAPPDIR)
+
+install-linux: resources/linux-icons
+	echo " [MKDIR] $(SHAREDIR)/applications"
+	mkdir -p "$(SHAREDIR)/applications"
+	echo " [CP]    resources/CraftOS-PC.desktop"
+	cp resources/CraftOS-PC.desktop "$(SHAREDIR)/applications"
+	
+	for dimension in 16 24 32 48 64 96 128 256 1024; do \
+	 	icondir="$(SHAREDIR)/icons/hicolor/$${dimension}x$${dimension}/apps"; \
+		echo " [MKDIR] $${icondir}"; \
+		mkdir -p "$${icondir}"; \
+		echo " [CP]    resources/linux-icons/$${dimension}.png)"; \
+		cp "resources/linux-icons/$${dimension}.png" "$${icondir}/craftos.png"; \
+	done
+
+install-headers:
+	echo " [MKDIR] $(INCLUDEDIR)"
+	mkdir -p "$(INCLUDEDIR)"
+	echo " [CP]    api"
+	cp -R api "$(INCLUDEDIR)/CraftOS-PC"
+
+install-bin: craftos
+	echo " [CP]    $(BINDIR)/craftos"
+	cp craftos "$(BINDIR)/craftos"
+
+# craftos2-lua does have a ``make install`` rule, but it installs a lot of
+# files that conflict with a standard Lua installation.
+install-liblua: craftos2-lua/src/liblua$(LIBEXT)
+	echo " [MKDIR] $(LIBDIR)"
+	mkdir $(LIBDIR)
+	cp craftos2-lua/src/liblua$(LIBEXT) $(LIBDIR)/$(LIBLUA_NAME)$(LIBEXT)
+
+install: $(INSTALL_TARGETS)
 
 uninstall:
 	echo " [RM]    $(DESTDIR)/craftos"
-	rm $(DESTDIR)/craftos
+	rm -f "$(BINDIR)/craftos"
+	rm -rf "$(INCLUDEDIR)/CraftOS-PC"
+	rm -f "$(SHAREDIR)/applications/CraftOS-PC.desktop"
+	rm -f "$(SHAREDIR)/icons/hicolor/*/apps/craftos.png"
+	rm -f "$(LIBDIR)/$(LIBLUA_NAME)$(LIBEXT)"
+	rm -rf "$(MACAPPDIR)/CraftOS-PC.app"
+
 
 test: craftos
 	./craftos --headless --script $(shell pwd)/resources/CraftOSTest.lua -d "$(shell mktemp -d)"
 
-.PHONY: all macapp clean rebuild install uninstall test
+.PHONY: all macapp clean rebuild install install-bin install-headers install-liblua install-linux install-darwin uninstall test
 .SILENT: