Linker failing using Up2.

Arduino Create "crashed" in Chrome, and reloaded itself, first try after reload gave a "bad gateway" and then subsequnet builds of Grove Library examples for Up2 and previously working sketches give linker error. with 'Missing file or directory' being displayed. Check the last few lines of this build scrip for details

./opt/arduino-builder/arduino-builder -compile -core-api-version 10611 -build-path /tmp/745265453/build -hardware opt/arduino-builder/hardware -hardware ./opt/cores -tools opt/arduino-builder/tools -tools ./opt/tools -built-in-libraries opt/libraries/latest -libraries /tmp/745265453/pinned -libraries /tmp/745265453/custom -fqbn arduino:mraa:intel_x86_64 -build-cache /tmp -logger humantags -verbose=true /tmp/745265453/SystemCalls_V1

Using board 'intel_x86_64' from platform in folder: /home/ubuntu/opt/cores/arduino/mraa

Using core 'linux' from platform in folder: /home/ubuntu/opt/cores/arduino/mraa

Detecting libraries used...

"/home/ubuntu/opt/tools/x86-linux-gcc/7.2.0/bin/x86_64-ubuntu16.04-linux-gnu-g++" -c -I. -w -g -O3 -nostdlib -DMRAA_BACKEND -DPLATFORM_PINMUXING_BUG -DN_I2C=3 -DN_SPI=3 -MMD -std=gnu++11 -mtune=corei7 -w -x c++ -E -CC -DARDUINO=10611 -DARDUINO_INTEL_X86_64 -DARDUINO_ARCH_MRAA -DARDUINO_LINUX "-I/home/ubuntu/opt/cores/arduino/mraa/cores/linux" "-I/home/ubuntu/opt/cores/arduino/mraa/variants/linux-x86-64" "/tmp/745265453/build/sketch/SystemCalls_V1.ino.cpp" -o "/dev/null"

Generating function prototypes...

"/home/ubuntu/opt/tools/x86-linux-gcc/7.2.0/bin/x86_64-ubuntu16.04-linux-gnu-g++" -c -I. -w -g -O3 -nostdlib -DMRAA_BACKEND -DPLATFORM_PINMUXING_BUG -DN_I2C=3 -DN_SPI=3 -MMD -std=gnu++11 -mtune=corei7 -w -x c++ -E -CC -DARDUINO=10611 -DARDUINO_INTEL_X86_64 -DARDUINO_ARCH_MRAA -DARDUINO_LINUX "-I/home/ubuntu/opt/cores/arduino/mraa/cores/linux" "-I/home/ubuntu/opt/cores/arduino/mraa/variants/linux-x86-64" "/tmp/745265453/build/sketch/SystemCalls_V1.ino.cpp" -o "/tmp/745265453/build/preproc/ctags_target_for_gcc_minus_e.cpp"

"/home/ubuntu/opt/arduino-builder/tools/arduino-preprocessor/0.1.5/arduino-preprocessor" "/tmp/745265453/build/preproc/ctags_target_for_gcc_minus_e.cpp" "" -- -std=gnu++11

Compiling sketch...

"/home/ubuntu/opt/tools/x86-linux-gcc/7.2.0/bin/x86_64-ubuntu16.04-linux-gnu-g++" -c -I. -w -g -O3 -nostdlib -DMRAA_BACKEND -DPLATFORM_PINMUXING_BUG -DN_I2C=3 -DN_SPI=3 -MMD -std=gnu++11 -mtune=corei7 -DARDUINO=10611 -DARDUINO_INTEL_X86_64 -DARDUINO_ARCH_MRAA -DARDUINO_LINUX "-I/home/ubuntu/opt/cores/arduino/mraa/cores/linux" "-I/home/ubuntu/opt/cores/arduino/mraa/variants/linux-x86-64" "/tmp/745265453/build/sketch/SystemCalls_V1.ino.cpp" -o "/tmp/745265453/build/sketch/SystemCalls_V1.ino.cpp.o"

Compiling libraries...

Compiling core...

"/home/ubuntu/opt/tools/x86-linux-gcc/7.2.0/bin/x86_64-ubuntu16.04-linux-gnu-g++" -c -I. -w -g -O3 -nostdlib -DMRAA_BACKEND -DPLATFORM_PINMUXING_BUG -DN_I2C=3 -DN_SPI=3 -MMD -std=gnu++11 -mtune=corei7 -DARDUINO=10611 -DARDUINO_INTEL_X86_64 -DARDUINO_ARCH_MRAA -DARDUINO_LINUX "-I/home/ubuntu/opt/cores/arduino/mraa/cores/linux" "-I/home/ubuntu/opt/cores/arduino/mraa/variants/linux-x86-64" "/home/ubuntu/opt/cores/arduino/mraa/variants/linux-x86-64/variant.cpp" -o "/tmp/745265453/build/core/variant.cpp.o"

Using precompiled core: /tmp/core/core_arduino_mraa_intel_x86_64_dd8104e414bd056a24f64272697b60b0.a

Linking everything together...

"/home/ubuntu/opt/tools/x86-linux-gcc/7.2.0/bin/x86_64-ubuntu16.04-linux-gnu-g++" -Wl,--gc-sections -lrt -w -Wl,--as-needed -o "/tmp/745265453/build/SystemCalls_V1.ino.elf" "-L/tmp/745265453/build" -Wl,--unresolved-symbols=report-all -Wl,--start-group "/tmp/745265453/build/sketch/SystemCalls_V1.ino.cpp.o" "/tmp/745265453/build/core/variant.cpp.o" "/tmp/745265453/build/../../core/core_arduino_mraa_intel_x86_64_dd8104e414bd056a24f64272697b60b0.a" {compiler.libraries.ldflags} /home/ubuntu/opt/cores/arduino/mraa/variants/linux-x86-64/libs/libmraa.a -lpthread -Wl,--end-group

x86_64-ubuntu16.04-linux-gnu-g++: error: {compiler.libraries.ldflags}: No such file or directory

exit status 1