lyd@ubuntu:~/pdf/pdfium$ gyp --depth=. pdfium.gyp -Dtarget_arch=x64
gyp: name 'clang' is not defined while evaluating condition 'clang==1' in pdfium.gyp
lyd@ubuntu:~/pdf/pdfium$ gyp --depth=. pdfium.gyp -Dtarget_arch=x64 -Dclang=1
gyp: name 'os_posix' is not defined while evaluating condition 'os_posix==1' in pdfium.gyp
lyd@ubuntu:~/pdf/pdfium$ gyp --depth=. pdfium.gyp -Dtarget_arch=x64 -Dclang=1 -Dos_posix=1
gyp: name 'component' is not defined while evaluating condition 'component=="shared_library"' in v8/tools/gyp/v8.gyp
lyd@ubuntu:~/pdf/pdfium$ gyp --depth=. pdfium.gyp -Dtarget_arch=x64 -Dclang=1 -Dos_posix=1 -Dcomponent=shared_library
gyp: name 'v8_optimized_debug' is not defined while evaluating condition 'v8_optimized_debug==0' in v8/tools/gyp/v8.gyp
lyd@ubuntu:~/pdf/pdfium$ gyp --depth=. pdfium.gyp -Dtarget_arch=x64 -Dclang=1 -Dos_posix=1 -Dcomponent=shared_library -Dv8_optimized_debug=0
gyp: Undefined variable icu_gyp_path in v8/tools/gyp/v8.gyp
