Fixes pr23591 test failures on hppa64-hpux and score-elf, and xfails
frv-linux and lm32-linux.
PR ld/23591
* testsuite/ld-elf/pr23591a.s,
* testsuite/ld-elf/pr23591b.s,
* testsuite/ld-elf/pr23591c.s: Don't start directives in first column.
* testsuite/ld-elf/pr23591.d: xfail frv-linux and lm32-linux.
Allow __start___sancov_cntrs as a local symbol.
When there are more than one input sections with the same section name,
SECNAME, linker picks the first one to define __start_SECNAME and
__stop_SECNAME symbols. When the first input section is removed by
comdat group, we need to check if there is still an output section
with section name SECNAME.
PR ld/23591
* ldlang.c (undef_start_stop): Lookup section in output with
the same name.
* testsuite/ld-elf/pr23591.d: New file.
* testsuite/ld-elf/pr23591a.s: Likewise.
* testsuite/ld-elf/pr23591b.s: Likewise.
* testsuite/ld-elf/pr23591c.s: Likewise.
