[Bug fortran/82233] New: execute_command_line causes program to stop when command fails (or does not exist)

[urbanjost at comcast dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82233

            Bug ID: 82233
           Summary: execute_command_line causes program to stop when
                    command fails (or does not exist)
           Product: gcc
           Version: 6.4.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: urbanjost at comcast dot net
  Target Milestone: ---

Created attachment 42191
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42191&action=edit
samples of execute_command_line that do and do not work with an unknown command

SYNOPSIS
   Many calls to execute_command_line(3f) cause an error and program
termination if commands do not
   exist or cause an error in gfortran 6.4.0; did not do this in 5.4.0

PROGRAMMING ENVIRONMENT
   OS:        CYGWIN_NT-10.0 2.9.0(0.318/5/3) 2017-09-08 10:19 x86_64 Cygwin
   COMPILER:  GNU Fortran (GCC) 6.4.0

EXAMPLE
   program boom
   call execute_command_line('notthere')
   end program boom

ERROR
   sh: notthere: command not found
   Fortran runtime error: EXECUTE_COMMAND_LINE: Invalid command line

   Error termination. Backtrace:
   #0  0xffffffffffffffff in ???
   #1  0xffffffffffffffff in ???
                :
                :