Making it so find_module_symvers can find multiple symvers when they are present, cleaning up cdsrfmswitch make a bit

 * work towards #335
 * modify find_module_symvers to user argparser and have a quiet option to make missing symvers files empty strings
 * update the src/epics/util/Makefile.in to pass the location of the rts cpu isolator symver file to feCodeGen.pl
 * update createKernelMakefile.pm to add the rts cpu isolator symvers file to the KBUILD_EXTRA_SYMBOLS for the module

Jameson Rollins authored 5 years ago and Rolf Bork committed 5 years ago

This makes discovery of the Module.symvers happen at model build time,
instead of at build tree creation/configuration.

A find_module_symvers script is included to find the Module.symvers
file, and it's used in the RCG Makefile to find module symvers files
at build time.

This reverts the top-level configure script changes from
8c01de98, restoring the configure
script and dropping the autoconf-generated configure step from the
build setup.