
This patch adds support for two environment variables to configure the device. ``LIBOMPTARGET_STACK_SIZE`` sets the amount of memory in bytes that each thread has for its stack. ``LIBOMPTARGET_HEAP_SIZE`` sets the amount of heap memory that can be allocated using malloc / free on the device. Reviewed By: jdoerfert Differential Revision: https://reviews.llvm.org/D106627