Drop obsolete AM_PROG_CC_C_O (#2342)

Drop obsolete AM_PROG_CC_C_O (#2342)

From automake manual:

"
 This is an obsolescent macro that checks that the C compiler
 supports the -c and -o options together. Note that, since
 Automake 1.14, the AC_PROG_CC is rewritten to implement such
 checks itself, and thus the explicit use of AM_PROG_CC_C_O
 should no longer be required.
"

This also changes an implicit build requirement of automake 1.5
to an explicit 1.14 or later requirement.