Without posting the entire build log:
/usr/bin/python2.7 /home/liamzebedee/Documents/workspace/moz-comm-central/mozilla/js/src/config/expandlibs_exec.py --depend .deps/libjs_static.a.pp --target libjs_static.a --extract -- ar cr libjs_static.a jsalloc.o jsanalyze.o jsapi.o jsarray.o jsatom.o jsbool.o jsclone.o jscntxt.o jscompartment.o jsdate.o jsdbgapi.o jsdhash.o jsdtoa.o jsexn.o jsfriendapi.o jsfun.o jsgc.o jscrashreport.o jsinfer.o jsinterp.o jsiter.o jslog2.o jsmath.o jsmemorymetrics.o jsnativestack.o jsnum.o jsobj.o json.o jsonparser.o jsopcode.o jsproxy.o jsprf.o jsprobes.o jspropertycache.o jspropertytree.o jsreflect.o jsscript.o jsstr.o jstypedarray.o jsutil.o jswatchpoint.o jsweakmap.o jsworkers.o ThreadPool.o Monitor.o ForkJoin.o jswrapper.o jsxml.o prmjtime.o sharkctl.o ArgumentsObject.o DateTime.o Debugger.o GlobalObject.o Object.o ObjectImpl.o ScopeObject.o Shape.o Stack.o String.o BytecodeCompiler.o BytecodeEmitter.o CharacterEncoding.o FoldConstants.o Intl.o NameFunctions.o ParallelArray.o ParseMaps.o ParseNode.o Parser.o SPSProfiler.o SelfHosting.o TokenStream.o TestingFunctions.o Profilers.o LifoAlloc.o Eval.o MapObject.o RegExpObject.o RegExpStatics.o RegExp.o RootMarking.o Marking.o Memory.o Statistics.o StoreBuffer.o Iteration.o Verifier.o StringBuffer.o Unicode.o Xdr.o Module.o MethodJIT.o StubCalls.o Compiler.o FrameState.o FastArithmetic.o FastBuiltins.o FastOps.o LoopState.o StubCompiler.o MonoIC.o PolyIC.o ImmutableSync.o InvokeHelpers.o Retcon.o TrampolineCompiler.o MIR.o BacktrackingAllocator.o Bailouts.o BitSet.o C1Spewer.o CodeGenerator.o CodeGenerator-shared.o Ion.o IonAnalysis.o IonBuilder.o IonCaches.o IonFrames.o IonMacroAssembler.o IonSpewer.o JSONSpewer.o LICM.o LinearScan.o LIR.o LiveRangeAllocator.o Lowering.o Lowering-shared.o MCallOptimize.o MIRGraph.o MoveResolver.o EdgeCaseAnalysis.o RegisterAllocator.o Snapshots.o Safepoints.o StupidAllocator.o TypeOracle.o TypePolicy.o ValueNumbering.o RangeAnalysis.o VMFunctions.o AliasAnalysis.o UnreachableCodeElimination.o CodeGenerator-x86-shared.o IonFrames-x86-shared.o MoveEmitter-x86-shared.o Assembler-x86-shared.o Lowering-x86-shared.o Lowering-x64.o CodeGenerator-x64.o Trampoline-x64.o Assembler-x64.o Bailouts-x64.o MacroAssembler-x64.o ExecutableAllocator.o PageBlock.o YarrInterpreter.o YarrPattern.o YarrSyntaxChecker.o YarrCanonicalizeUCS2.o ExecutableAllocatorPosix.o OSAllocatorPosix.o ARMAssembler.o MacroAssemblerARM.o MacroAssemblerX86Common.o YarrJIT.o CTypes.o Library.o jsperf.o pm_linux.o ctypes/libffi/.libs/libffi.a
Traceback (most recent call last):
File "/home/liamzebedee/Documents/workspace/moz-comm-central/mozilla/js/src/config/expandlibs_exec.py", line 26, in <module>
from expandlibs import ExpandArgs, relativize, isObject, ensureParentDir, ExpandLibsDeps
File "/home/liamzebedee/Documents/workspace/moz-comm-central/mozilla/js/src/config/expandlibs.py", line 31, in <module>
import expandlibs_config as conf
File "/home/liamzebedee/Documents/workspace/moz-comm-central/mozilla/js/src/config/expandlibs_config.py", line 5, in <module>
from buildconfig import substs
ImportError: No module named buildconfig
make[5]: *** [libjs_static.a] Error 1
make[5]: Leaving directory `/home/liamzebedee/Documents/workspace/moz-comm-central/obj-x86_64-unknown-linux-gnu/mozilla/js/src'
make[4]: *** [libs_tier_js] Error 2
make[4]: Leaving directory `/home/liamzebedee/Documents/workspace/moz-comm-central/obj-x86_64-unknown-linux-gnu/mozilla'
make[3]: *** [tier_js] Error 2
make[3]: Leaving directory `/home/liamzebedee/Documents/workspace/moz-comm-central/obj-x86_64-unknown-linux-gnu/mozilla'
make[2]: *** [default] Error 2
make[2]: Leaving directory `/home/liamzebedee/Documents/workspace/moz-comm-central/obj-x86_64-unknown-linux-gnu/mozilla'
make[1]: *** [default] Error 2
make[1]: Leaving directory `/home/liamzebedee/Documents/workspace/moz-comm-central/obj-x86_64-unknown-linux-gnu'
make: *** [build] Error 2