bug#6734: "inline" overused in .c files?

[Paul Eggert]

I noticed thirteen "inline"s in coreutils/src/sort.c.  Just for fun, I
removed them all.  In ten cases, removing "inline" made no difference to
the generated machine code on my platform (RHEL 5, x86-64, GCC 4.1.2,
compiled with the typical gcc -O2).  In the three sort.c functions
that were exceptions (queue_insert, write_unique, check_insert),
removing "inline" made the overall code a tad shorter with no
measurable change to CPU performance.

Is there a reason those "inline"s are in there?  If not, I'm inclined
to remove them.  I can see a use for "static inline" in .h files, as
this asks the compiler not to warn about unused functions, but as far
as I know, it's typically not necessary to use "inline" in .c files
these days, as the compiler is typically smart enough.

I've checked this only for coreutils/src/sort.c but perhaps the same
argument applies to other source files in coreutils or other GNU apps, so
I'll CC: this to bug-gnulib for more-general comment.