inpcom.c, cleanup inp_readall() #1/7, introduce inp_read()
inpcom.c, cleanup inp_readall() #2/7, move inp_read() prolog to inp_readall()
inpcom.c, cleanup inp_readall() #3/7, return `line_number' too
inpcom.c, cleanup inp_readall() #4/7, move inp_read() epilog to inp_readall()
inpcom.c, cleanup inp_readall() #5/7, use `rv . line_number' itself
inpcom.c, cleanup inp_readall() #6/7, tautology `call_depth == 0'
inpcom.c, cleanup inp_readall() #7/7, drop misleading comment
inpcom.c: MSVC compatibility
fix criterion to start `.lib' and `.global gnd' processing
correct the step incrementing type to SENS_LINEAR
inpcom.c, add missing condition `!comfile' for .title and .end processing
bug fix for commit "inpcom.c, cleanup inp_readall() #4/7, move inp_read() epilog to inp_readall()"

fix ngspice segfault when invoked with no arguments
there was a "return NULL" in front of the epilog
  invalidating this code transformation