Failed building SWIG java binding for android (x86 target)

[riza]

Currently builing SWIG java binding for android (x86 target) failed.

libwebrtc-x86-unknown-linux-android.a(aec_core.o):aec_core.c:function WebRtcAec_CreateAec: error: undefined reference to 'WebRtc_GetCPUInfo'
libwebrtc-x86-unknown-linux-android.a(aec_core.o):aec_core.c:function WebRtcAec_CreateAec: error: undefined reference to 'WebRtcAec_InitAec_SSE2'
libwebrtc-x86-unknown-linux-android.a(aec_rdft.o):aec_rdft.c:function aec_rdft_init: error: undefined reference to 'WebRtc_GetCPUInfo'
libwebrtc-x86-unknown-linux-android.a(aec_rdft.o):aec_rdft.c:function aec_rdft_init: error: undefined reference to 'aec_rdft_init_sse2'

It was reported that r6066 has caused this. The fix is intended to fix build error using NDK r20b, however it seems to trigger another error which also effect older NDK.
Until a better solution is found, it is recommended to use older NDK (e.g: r19) without the the fix on r6066.

Thanks to Samuel Fornes for the report.

[nanang]

In 6120:

Fix #2256: Mini refactored Android configure script:

• added CXXFLAGS & LDFLAGS parsing (from ndk-build output), CXXFLAGS was set to CFLAGS.
• updated WebRTC instruction set to use SSE2, was generic, for Android emulator (x86 ABI).
• updated C++ library/STL backend to use c++_shared, somehow '-lc++_static' is ignored after the refactor, also the official NDK docs mentions that c++_static may cause undefined behavior for app with multiple shared libraries (note pjsua2 app may use other shared libraries).

[nanang]

In 6121:

Re #2256: Fixed build error for iOS target due to changes in r6120.

[nanang]

In 6122:

Re #2256: Readjusted build configs (after r6120 & r6121) to accomodate the convention that CXXFLAGS always includes CFLAGS in all PJSIP modules.