Notes on Compiling Various C Libraries for the Android NDK

It’s not so easy! You can’t just use the “./configure and make” build system most libraries come with. Instead, at the very least you’re going to have to create your own custom “Android.mk”, which lists the .c files you need and sets up gcc correctly.

Well, that’s the best-case scenario. Some libraries require some minimal patching or other trickery. Here are my notes for some.

SDL 2.0.3

Conveniently comes with a ready-made “Android.mk” in the main directory, as well as a demo application under “android-project”.
However... if you run “./configure” even once, it will regenerate “SDL_config.h” and ruin it for Android builds. Be sure to use a freshly downloaded version of the file.

SDL_mixer 2.0.0

Comes with an Android.mk, which can also compile in its dependencies.
However, I needed to patch it a bit to work with newer versions of libogg and libvorbis. In particular, you can do without the -DOGG_USE_TREMOR gcc flag.

libogg 1.3.1

You need a “config_types.h” header file, but this can only be generated if you run “./configure”. I did so on Linux (x64) and it seems to work fine for Android builds.

libpng 1.6.9

You need a “pnglibconf.h” header file. There’s one you can use in the distribution, in “scripts/pnglibconf.h.prebuilt”.

Pixman 0.32.4

gcc flags are different for x86 and ARM platforms. Here’s what I used in Android.mk:

ifeq ($(TARGET_ARCH),x86)
LOCAL_CFLAGS := -DPACKAGE="pixman" -D_USE_MATH_DEFINES -DPIXMAN_NO_TLS -DUSE_X86_MMX -DUSE_SSE2
else
LOCAL_CFLAGS := -DPACKAGE="pixman" -D_USE_MATH_DEFINES -DPIXMAN_NO_TLS -DUSE_ARM_NEON -DUSE_ARM_SIMD
endif

You need a “pixman_version.h” header file, but this can only be generated if you run “./configure”. I did so on Linux (x64) and it seems to work fine for Android builds.
The “pixman-implementation.c” code tries to load all implementations, but this will fail on compilation if the implementations are not there. I patched the “_pixman_choose_implementation” function like so:

#if defined(USE_ARM_SIMD) || defined(USE_ARM_NEON) || defined(USE_ARM_IWMMXT)
    imp = _pixman_arm_get_implementations (imp);
#else
    imp = _pixman_x86_get_implementations (imp);
#endif
    //imp = _pixman_ppc_get_implementations (imp);
    //imp = _pixman_mips_get_implementations (imp);

Cairo 1.12.16

gcc flags: -DPACKAGE_VERSION=“cairo” -DCAIRO_NO_MUTEX -DHAVE_STDINT_H -DHAVE_UINT64_T
You need “cairo-features.h” and “cairo-version.h” header files, but they can only be generated if you run “./configure”. I did so on Linux (x64) and it seems to work fine for Android builds.
“cairo-output-stream.c” won’t compile due to Android’s less-than-Posix implementation of localization. You need to patch the “_cairo_dtostr” function:

#ifndef __ANDROID__
struct lconv *locale_data;
#endif
...
#ifndef __ANDROID__
locale_data = localeconv ();
decimal_point = locale_data->decimal_point;
#else
decimal_point = ".";
#endif

(I’ve opened a bug about this.)

Lua 5.2.3

gcc flags: -DLUA_ANSI
Again, a problem with Android’s less-than-Posix implementation of localization. You need to patch “luaconf.h”. Simple add this at the bottom:

#ifdef __ANDROID__
#define getlocaledecpoint() ('.')
#endif

exceptions4c 3.0.0

gcc flags: -DE4C_THREADSAFE -DMISSING_PTHREAD_CANCEL

SimCList 1.6

gcc flags: -DSIMCLIST_NO_DUMPRESTORE

Dec 31, 1969, 18:00 CST

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Notes on Compiling Various C Libraries for the Android NDK