build: add --v8-target-arch and cross compiling options

Checklist

• commit message follows commit guidelines

Affected core subsystem(s)

build

Description of change

• Add --v8-target-arch option to apply a correct v8_target_arch like x87 in config.gypi while --dest-cpu=ia32.
• Add --host-cc, --host-cxx, --host-ar options to set environment variables required for a cross compiling process.

Signed-off-by: Eugene Bolshakov pub@relvarsoft.com