[Android Q&A, Help & Troubleshooting] AmulyaX:
This is the second time I tried building from scratch and this has occurred again. I am building AEX 5.1 from 8.1 64 bit device tree and it gets stuck at 42% stating

[ 42% 38993/91195] //art/runtime:art_operator_srcs generate

I am gonna paste the whole screen output I have at present if it helps

target C++: libvold <= system/vold/Disk.cpp
6 warnings generated.
Suppressed 6 warnings (5 in non-user code, 1 with check filters).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
[ 41% 38225/91195] build /home/amulya_b520/aex5/out/target/product/addison/obj/STATIC_LIBRARIES/libvold_intermediates/VolumeManager.o
target C++: libvold <= system/vold/VolumeManager.cpp
6 warnings generated.
Suppressed 6 warnings (5 in non-user code, 1 with check filters).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
[ 41% 38250/91195] build /home/amulya_b520/aex5/out/target/product/addison/obj/STATIC_LIBRARIES/libvold_intermediates/KeyStorage.o
target C++: libvold <= system/vold/KeyStorage.cpp
6 warnings generated.
Suppressed 6 warnings (5 in non-user code, 1 with check filters).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
[ 41% 38270/91195] build /home/amulya_b520/aex5/out/target/product/addison/obj/STATIC_LIBRARIES/libvold_intermediates/VolumeBase.o
target C++: libvold <= system/vold/VolumeBase.cpp
6 warnings generated.
Suppressed 6 warnings (5 in non-user code, 1 with check filters).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
[ 41% 38297/91195] build /home/amulya_b520/aex5/out/target/product/addison/obj/STATIC_LIBRARIES/libvold_intermediates/Ext4Crypt.o
target C++: libvold <= system/vold/Ext4Crypt.cpp
6 warnings generated.
Suppressed 6 warnings (5 in non-user code, 1 with check filters).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
[ 41% 38300/91195] build /home/amulya_b520/aex5/out/target/product/addison/obj/STATIC_LIBRARIES/libwpa_hidl_intermediates/hidl/1.0/hidl_manager.o
target C++: libwpa_hidl <= external/wpa_supplicant_8/wpa_supplicant/hidl/1.0/hidl_manager.cpp
[ 41% 38301/91195] build /home/amulya_b520/aex5/out/target/product/addison/obj/STATIC_LIBRARIES/libwpa_hidl_intermediates/libwpa_hidl.a
target StaticLib: libwpa_hidl (/home/amulya_b520/aex5/out/target/product/addison/obj/STATIC_LIBRARIES/libwpa_hidl_intermediates/libwpa_hidl.a)
[ 42% 38326/91195] build '/home/amulya_b520/aex5/out/target/product/addison/obj/STATIC...castradio@1.1-utils-lib_intermediates/android.hardware.broadcastradio@1.1-utils-lib.a'
target Prebuilt: android.hardware.broadcastradio@1.1-utils-lib (/home/amulya_b520/aex5/out/target/product/addison/obj/STATIC_LIBRARIES/android.hardware.broadcastradio@1.1-util
s-lib_intermediates/android.hardware.broadcastradio@1.1-utils-lib.a)
[ 42% 38332/91195] build '/home/amulya_b520/aex5/out/target/product/addison/obj_arm/ST...castradio@1.1-utils-lib_intermediates/android.hardware.broadcastradio@1.1-utils-lib.a'
target Prebuilt: android.hardware.broadcastradio@1.1-utils-lib_32 (/home/amulya_b520/aex5/out/target/product/addison/obj_arm/STATIC_LIBRARIES/android.hardware.broadcastradio@1
.1-utils-lib_intermediates/android.hardware.broadcastradio@1.1-utils-lib.a)
[ 42% 38401/91195] build /home/amulya_b520/aex5/out/target/product/addison/obj/STATIC_LIBRARIES/libvold_intermediates/Utils.o
target C++: libvold <= system/vold/Utils.cpp
6 warnings generated.
Suppressed 7 warnings (5 in non-user code, 1 NOLINT, 1 with check filters).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
[ 42% 38403/91195] build /home/amulya_b520/aex5/out/target/product/addison/obj/STATIC_LIBRARIES/libvold_intermediates/libvold.a
target StaticLib: libvold (/home/amulya_b520/aex5/out/target/product/addison/obj/STATIC_LIBRARIES/libvold_intermediates/libvold.a)
[ 42% 38640/91195] build '/home/amulya_b520/aex5/out/target/product/addison/obj/STATIC...droid.hardware.health@1.0-convert_intermediates/android.hardware.health@1.0-convert.a'
target Prebuilt: android.hardware.health@1.0-convert (/home/amulya_b520/aex5/out/target/product/addison/obj/STATIC_LIBRARIES/android.hardware.health@1.0-convert_intermediates/
android.hardware.health@1.0-convert.a)
[ 42% 38993/91195] //art/runtime:art_operator_srcs generate