Makefile changes to be rebased back

Makefile

@@ -82,17 +82,19 @@ LINK_FLAGS = $(COMMON_FLAGS)\
 	-s EXPORTED_RUNTIME_METHODS=['callMain']\
 	--emrun
 
-CPPS := $(shell ls source/*.cpp) $(shell ls source/text/*.cpp)
-CPPS_EXCEPT_MAIN := $(shell ls source/*.cpp | grep -v main.cpp) $(shell ls source/text/*.cpp)
+CPPS := $(shell ls source/*.cpp) $(shell ls source/text/*.cpp) $(shell ls source/ship/*.cpp)
+CPPS_EXCEPT_MAIN := $(shell ls source/*.cpp | grep -v main.cpp) $(shell ls source/text/*.cpp) $(shell ls source/ship/*.cpp)
 TEMP := $(subst source/,build/emcc/,$(CPPS))
 OBJS := $(subst .cpp,.o,$(TEMP))
 TEMP := $(subst source/,build/emcc/,$(CPPS_EXCEPT_MAIN))
 OBJS_EXCEPT_MAIN := $(subst .cpp,.o,$(TEMP))
-HEADERS := $(shell ls source/*.h*) $(shell ls source/text/*.h*)
+HEADERS := $(shell ls source/*.h*) $(shell ls source/text/*.h*) $(shell ls source/ship/*.h*) $(shell ls source/comparators/*.h*)
 
 build/emcc/%.o: source/%.cpp $(HEADERS) libjpeg-turbo-2.1.0/libturbojpeg.a
 	@mkdir -p build/emcc
 	@mkdir -p build/emcc/text
+	@mkdir -p build/emcc/ship
+	@mkdir -p build/emcc/comparators
 	$(CXX) $(CFLAGS) -c $< -o $@
 
 lib/emcc/libendless-sky.a: $(OBJS_EXCEPT_MAIN)

readme-developer.md

@@ -0,0 +1,21 @@
+## Building for the web:
+
+Mac and Linux (Windows not supported):
+
+Install Emscripten following the instructions at https://emscripten.org/docs/getting_started/downloads.html
+Use the latest version and source the emsdk_env.sh file so you can run commands like emcc, em++ and emmake.
+The last time I checked, this looked like:
+
+```
+  $ git clone https://github.com/emscripten-core/emsdk.git
+  $ cd emsdk
+  $ ./emsdk install 3.1.24
+  $ ./emsdk activate 3.1.24
+  $ source ./emsdk_env.sh  # you'll need to run this one each time you open a new terminal
+```
+
+Now back in the endless-sky repo directory run: (maybe you need to install make, wget, and tar first? I figure those should be everywhere already)
+
+```
+  $ make dev
+```