[Android Q&A, Help & Troubleshooting] bypass23:
in AudioHardware.h line 28 change :

namespace android {

as mentioned to :

namespace android_audio_legacy {

I tried it myself just by curiosity and it leads to these errors :

target thumb C++: libaudio <= hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp
In file included from hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:37:
hardware/msm7k/libaudio-qsd8k/AudioHardware.h:318: error: 'Mutex' does not name a type
hardware/msm7k/libaudio-qsd8k/AudioHardware.h:328: error: ISO C++ forbids declaration of 'SortedVector' with no type
hardware/msm7k/libaudio-qsd8k/AudioHardware.h:328: error: expected ';' before '<' token
hardware/msm7k/libaudio-qsd8k/AudioHardware.h:337: error: 'Mutex' does not name a type
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:92: error: 'AudioHardware' has not been declared
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:102: error: 'AudioHardware' has not been declared
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:102: error: ISO C++ forbids declaration of 'AudioHardware' with no type
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp: In function 'int android::AudioHardware()':
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:103: error: only constructors take base initializers
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:109: error: 'TTY_MODE_OFF' was not declared in this scope
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:112: error: 'msm_bt_endpoint' was not declared in this scope
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:112: error: expected primary-expression before ')' token
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:116: error: invalid type in declaration before ';' token
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:118: error: 'doA1026_init' was not declared in this scope
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:124: error: 'mNumBTEndpoints' was not declared in this scope
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:125: error: 'mInit' was not declared in this scope
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:126: error: return-statement with no value, in function returning 'int'
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:131: error: return-statement with no value, in function returning 'int'
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:158: error: 'mNumBTEndpoints' was not declared in this scope
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:160: error: 'mBTEndpoints' was not declared in this scope
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:160: error: expected type-specifier before 'msm_bt_endpoint'
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:160: error: expected ';' before 'msm_bt_endpoint'
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:161: error: 'mInit' was not declared in this scope
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:164: error: expected primary-expression before 'int'
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:164: error: expected ')' before 'int'
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:167: error: return-statement with no value, in function returning 'int'
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:169: error: 'snd_get_bt_endpoint' cannot be used as a function
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:206: error: no return statement in function returning non-void
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp: At global scope:
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:208: error: expected constructor, destructor, or type conversion before '::' token
hardware/msm7k/libaudio-qsd8k/AudioHardware.cpp:2025: error: expected '}' at end of input
make: *** [out/target/product/passion/obj/SHARED_LIBRARIES/libaudio_intermediates/AudioHardware.o] Error 1