Issue 1414 - Document how to build libadblockplus for Android

README.md

Index: README.md
===================================================================
--- a/README.md
+++ b/README.md
@@ -53,21 +53,33 @@
 
 ### Supported compilers
 
 You need a C++11 compatible compiler to build libadblockplus.
 
 The compilation was tested with the following compilers:
 * g++ 4.8
 * Microsoft Visual Studio 2010, 2012
-* clang 3.4 for Android (from android-ndk-r9)
+* clang 3.4 for Android (from android-ndk-r9, r10c)

[sergei, 2016/06/08 15:32:35]

It's actually can be quite tricky to find the link to these NDKs because they
are not the latest ones and as far as I remember there are no links to them on
google's web site. Therefore could you please add links to them at the end of
"Supported compilers" section.

[sergei, 2016/06/08 15:32:35]

It also makes sense to say may be after the list of compilers that we have to
use one of these NDK because they contain gcc-4.6 which is required to compile
v8.

[sergei, 2016/06/10 11:36:01]

Yeah, but unfortunately we cannot achieve it right now because this dependency
origins from the version of v8. Currently v8 requires gcc-4.6, the next version
(https://issues.adblockplus.org/ticket/1197) requires gcc-4.8. Since #1197 is
landed I will look for the next version to update it further to suppor visual
stuio 2015. After the latter update I hope it will be possible to use latest
NDK, recent versions of v8 require clang and I don't see any concrete version
although I have not tried to compile it yet.

[sergei, 2016/06/10 11:36:01]

Honestly I personally have not tried to compile it with gcc-4.9 from any of
android ndk. It requires at least to dig into v8 gyp and Makefiles and according
to previous experience v8 is quite fragile in terms of any modifications, so I
would like to avoid it and rather update v8 to a version which does not require
old version of compiler.

[anton, 2016/06/14 07:16:46]

i've tried to compile with gcc-4.9 from r11c symlinked to gcc-4.6 and it's not
working

 * clang 3.6 for OS X
 
 If you have a question about another compiler please [create an issue](https://issues.adblockplus.org/).
 
+### Building for Android

[sergei, 2016/06/08 15:32:35]

I think it should be before "Supported compilers" because there are already
"Unix" and "Windows" and this section is very close to them.

May be it will be even better to have "Supported compilers" as the first section
of "Building".

[anton, 2016/06/14 07:16:46]

Done.

[anton, 2016/06/14 07:16:46]

Done.

+
+First set ANDROID_NDK_ROOT environment variable to your Android NDK  directory.

[sergei, 2016/06/08 15:32:35]

It would be better if you could include an example.

[sergei, 2016/06/08 15:32:35]

There is additional space character between NDK and directory.

[sergei, 2016/06/10 11:36:01]

Fair enough, albeit I guess nobody is trying to compile libdblockplus for
Android on Windows.

[anton, 2016/06/14 07:16:46]

Done.

[anton, 2016/06/14 07:16:46]

Not sure it's needed as i assume people trying to compile it are a king of
advanced users and they (should) know how to do this basic stuff. Also it
relates to OS so i believe it's out of scope of this readme

+
+To build for *x86* arch run:
+
+    make android_x86
+
+To build for *arm* arch run:
+
+    make android_arm
+
 Usage
 -----
 
 You can use libadblockplus to build an ad blocker. Or, strictly speaking, a web
 content filter. Just like Adblock Plus, it can detect resources that should be
 blocked based on their URL and context information, and generate CSS selectors
 to hide DOM elements.