testsuite: i386: Require ifunc support in gcc.target/i386/pr98100.c

testsuite: i386: Require ifunc support in gcc.target/i386/pr98100.c

The new gcc.target/i386/pr98100.c test FAILs on Solaris/x86:

FAIL: gcc.target/i386/pr98100.c (test for excess errors)

Excess errors:
/vol/gcc/src/hg/master/local/gcc/testsuite/gcc.target/i386/pr98100.c:6:1: error: the call requires 'ifunc', which is not supported by this target

Fixed as follows.

Tested on i386-pc-solaris2.11 and x86_64-pc-linux-gnu.

2020-12-07  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

	gcc/testsuite:
	* gcc.target/i386/pr98100.c: Require ifunc support.