Improve Android support

Improve Android support

This patch remove many Android-specific #ifdefs from the Breakpad
source code. This is achieved by providing "fixed-up" platform
headers (e.g. <signal.h> or <sys/user,h>), in the new directory
src/common/android/include/, which masks differences between
the NDK and GLibc headers.

The old "android_link.h" and "android_ucontext.h" are moved
and renamed.

This also requires putting this directory as the first
include path during Android-hosted builds, hence the
modification of Makefile.am and configure.ac
Committed: https://code.google.com/p/google-breakpad/source/detail?r=1017

[digit]

This is the "fixed" version of 427004 rebased on top of current master.

This includes new fixed NDK headers that will be used in upcoming patches to fix
the following too:

 - Fix the processor + tools build for Android
 - Fix the Android/x86 build.
 - Fix "make check" when targetting Android
 - Allow "make check" to run on a connected device through a wrapper shell
called with  TESTS_ENVIRONMENT.

[Mark Mentovai]

http://breakpad.appspot.com/434002/diff/1001/src/common/android/include/elf.h
File src/common/android/include/elf.h (right):

http://breakpad.appspot.com/434002/diff/1001/src/common/android/include/elf.h...
src/common/android/include/elf.h:36: __BEGIN_DECLS
This is dangerous because it’s a glibc-private macro that you’re mooching off,
and you’re hoping that one of the other two headers you’ve included will bring
it in. If you’re intent on using it, you should #include <sys/cdefs.h>, but I’d
actually rather see you just write

#ifdef __cplusplus
extern "C" {
#endif  // __cplusplus

yourself. Same for __END_DECLS. This applies to other files as well.

http://breakpad.appspot.com/434002/diff/1001/src/common/android/include/signal.h
File src/common/android/include/signal.h (right):

http://breakpad.appspot.com/434002/diff/1001/src/common/android/include/signa...
src/common/android/include/signal.h:45: #include <../../usr/include/signal.h>
This binds you to a specific location for your Breakpad checkout relative to
/usr. You’ll need to find a better solution. The same comment applies to other
files.

[digit]

http://breakpad.appspot.com/434002/diff/1001/src/common/android/include/elf.h
File src/common/android/include/elf.h (right):

http://breakpad.appspot.com/434002/diff/1001/src/common/android/include/elf.h...
src/common/android/include/elf.h:36: __BEGIN_DECLS
I agree. I have fixed it in the latest patch.

http://breakpad.appspot.com/434002/diff/1001/src/common/android/include/signal.h
File src/common/android/include/signal.h (right):

http://breakpad.appspot.com/434002/diff/1001/src/common/android/include/signa...
src/common/android/include/signal.h:45: #include <../../usr/include/signal.h>
I have removed the two headers files that require this work-around for now.
Modifying the Linux exception_handler.h to include <sys/ucontext.h> seems to be
enough.

As for stdlib.h / mkdtemp(), this is only for unit testing and will be addressed
differently in another patch.

[Mark Mentovai]

LGTM

http://breakpad.appspot.com/434002/diff/7001/src/common/android/include/elf.h
File src/common/android/include/elf.h (right):

http://breakpad.appspot.com/434002/diff/7001/src/common/android/include/elf.h...
src/common/android/include/elf.h:156: }
Optional, but I usually write

}  // extern "C"

the same way we write when we close namespaces, just to make it clear what this
does (and that it’s closing an extern "C" and not a namespace).

You can do the same in the other extern "C"s in this change if you want.

[digit]

http://breakpad.appspot.com/434002/diff/7001/src/common/android/include/elf.h
File src/common/android/include/elf.h (right):

http://breakpad.appspot.com/434002/diff/7001/src/common/android/include/elf.h...
src/common/android/include/elf.h:156: }
Done, thanks.