Add argparse as submodule

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "src/argparse"]
+	path = src/argparse
+	url = https://github.com/cofyc/argparse

CMakeLists.txt

@@ -12,7 +12,7 @@ find_package(PNG)
 find_package(LibSndFile)
 
 set(LIB_C_SOURCE_FILES src/color.c src/dsp.c src/filter.c src/image.c src/algebra.c src/libs/median.c)
-set(EXE_C_SOURCE_FILES src/main.c src/pngio.c src/libs/argparse.c)
+set(EXE_C_SOURCE_FILES src/main.c src/pngio.c src/argparse/argparse.c)
 set(LIB_C_HEADER_FILES src/apt.h)
 
 # Link with static library for aptdec executable, so we don't need to set the path

README.md

@@ -23,7 +23,7 @@ The input audio format can be anything supported by `libsndfile` (although only
 
 ```sh
 sudo apt install cmake git gcc libsndfile-dev libpng-dev
-git clone https://github.com/Xerbo/aptdec.git && cd aptdec
+git clone --recursive https://github.com/Xerbo/aptdec.git && cd aptdec
 cmake -B build
 cmake --build build
 # Resulting binary is build/aptdec

src/argparse

@@ -0,0 +1 @@
+Subproject commit c612dc03958cdbd538ca306d61853b643a435933