$ ./mach build
 Config object not found by mach.
 0:06.19 Clobber not needed.
 0:06.19 Adding make options from None
    MOZ_OBJDIR=c:/mozilla-source/mozilla-central/obj-x86_64-pc-mingw32
    OBJDIR=c:/mozilla-source/mozilla-central/obj-x86_64-pc-mingw32
 0:06.24 c:\mozilla-build\bin\mozmake.EXE -f client.mk -s configure
 0:06.33 cd c:/mozilla-source/mozilla-central/obj-x86_64-pc-mingw32
 0:06.35 c:/mozilla-source/mozilla-central/configure
 0:06.70 Reexecuting in the virtualenv
 0:07.65 checking for vcs source checkout... hg
 0:07.69 checking for a shell... c:/mozilla-build/msys/bin/sh.exe
 0:07.70 checking for host system type... x86_64-pc-mingw32
 0:07.70 checking for target system type... x86_64-pc-mingw32
 0:08.06 checking whether cross compiling... no
 0:08.32 checking for the target C compiler... c:/Users/Utkarsh/.mozbuild/clang/bin/clang-cl.exe
 0:08.56 checking whether the target C compiler can be used... yes
 0:08.72 checking for Python 3... c:/mozilla-build//python3/python3.exe (3.6.5)
 0:08.72 checking for hg... c:/mozilla-build/python/Scripts/hg.exe
 0:12.67 checking for Mercurial version... 4.9
 0:13.47 checking for sparse checkout... no
 0:13.47 checking for yasm... c:/mozilla-build/bin/yasm.exe
 0:13.49 checking yasm version... 1.3.0
 0:13.51 checking for nasm... not found
 0:13.51 checking the target C compiler version... 7.0.0
 0:13.61 checking the target C compiler works... yes
 0:13.61 checking for the target C++ compiler... c:/Users/Utkarsh/.mozbuild/clang/bin/clang-cl.exe
 0:13.69 checking whether the target C++ compiler can be used... yes
 0:13.69 checking the target C++ compiler version... 7.0.0
 0:13.77 checking the target C++ compiler works... yes
 0:13.77 checking for the host C compiler... c:/Users/Utkarsh/.mozbuild/clang/bin/clang-cl.exe
 0:13.91 checking whether the host C compiler can be used... yes
 0:13.91 checking the host C compiler version... 7.0.0
 0:14.00 checking the host C compiler works... yes
 0:14.00 checking for the host C++ compiler... c:/Users/Utkarsh/.mozbuild/clang/bin/clang-cl.exe
 0:14.08 checking whether the host C++ compiler can be used... yes
 0:14.08 checking the host C++ compiler version... 7.0.0
 0:14.16 checking the host C++ compiler works... yes
 0:14.25 checking for 64-bit OS... yes
 0:14.38 checking for Windows SDK... 0x0a00 in 'C:\Program Files (x86)\Windows Kits\10\'
 0:14.38 checking for Universal CRT SDK... 10.0.17763.0 in 'C:\Program Files (x86)\Windows Kits\10\'
 0:14.40 checking for the Debug Interface Access SDK... C:\PROGRA~2\MICROS~2\2017\COMMUN~1\DIA SDK
 0:14.41 checking for mt... C:/PROGRA~2/WI3CF2~1/10/bin/100177~1.0/x64/mt.exe
 0:14.44 checking whether MT is really Microsoft Manifest Tool... yes
 0:14.45 checking for linker... c:/Users/Utkarsh/.mozbuild/clang/bin/lld-link.exe
 0:14.46 checking for host_linker... c:/Users/Utkarsh/.mozbuild/clang/bin/lld-link.exe
 0:14.48 checking for makecab... c:/WINDOWS/System32/makecab.exe
 0:14.48 checking for llvm_profdata... c:/Users/Utkarsh/.mozbuild/clang/bin/llvm-profdata.exe
 0:14.50 checking for the assembler... C:/PROGRA~2/MICROS~2/2017/COMMUN~1/VC/Tools/MSVC/1416~1.270/bin/HostX64/x64/ml64.exe
 0:14.54 checking whether the C compiler supports -fsanitize=fuzzer-no-link... no
 0:14.56 checking for rc... C:/PROGRA~2/WI3CF2~1/10/bin/100177~1.0/x64/rc.exe
 0:14.56 checking for ar... c:/Users/Utkarsh/.mozbuild/clang/bin/llvm-lib.exe
 0:14.58 checking for pkg_config... not found
 0:14.82 checking for stdint.h... yes
 0:14.98 checking for inttypes.h... yes
 0:15.17 checking for malloc.h... yes
 0:15.25 checking for alloca.h... no
 0:15.33 checking for sys/byteorder.h... no
 0:15.41 checking for getopt.h... no
 0:15.49 checking for unistd.h... no
 0:15.58 checking for nl_types.h... no
 0:15.71 checking for cpuid.h... yes
 0:15.82 checking for sys/statvfs.h... no
 0:15.90 checking for sys/statfs.h... no
 0:15.99 checking for sys/vfs.h... no
 0:16.07 checking for sys/mount.h... no
 0:16.14 checking for sys/quota.h... no
 0:16.24 checking for sys/queue.h... no
 0:16.36 checking for sys/types.h... yes
 0:16.44 checking for netinet/in.h... no
 0:16.53 checking for byteswap.h... no
 0:16.62 checking for perf_event_open system call... no
 0:16.67 checking for cbindgen... c:/Users/Utkarsh/.mozbuild/cbindgen/cbindgen.exe
 0:16.69 checking cbindgen version...
 0:16.69 DEBUG: Executing: `c:/Users/Utkarsh/.mozbuild/cbindgen/cbindgen.exe --version`
 0:16.69 ERROR: cbindgen version 0.6.7 is too old. At least version 0.7.1 is required.
 0:16.69 Please update using 'cargo install cbindgen --force' or running
 0:16.69 './mach bootstrap', after removing the existing executable located at
 0:16.69 c:/Users/Utkarsh/.mozbuild/cbindgen/cbindgen.exe.
 0:16.77 *** Fix above errors and then restart with\
 0:16.77                "./mach build"
 0:16.80 mozmake.EXE: *** [client.mk:115: configure] Error 1