This library provides utilities for building and runnign C
programs with a system-installed C compiler. Currently the only
supported compiler is 6.1 External Processes Raised when a
system error occurs in executing an external process. The path
to the GCC executable. By default, this is initialized to: Runs
a C program with GCC, using the value of current-gcc to find the
GCC executable. The program source is obtained by invoking
print-source, which is run in a continuation barrier to prevent
re-entrant evaluation. The external program is built to a
temporary file which is automatically deleted after the program
terminates. The external program is run in a separate thread, so
this procedure returns before the program necessarily
terminates. The procedure produces two values, input ports for
reading from the external program’s stdout and stderr ports.