Keep .GCC.command.line sections of LTO objetcs

Keep .GCC.command.line sections of LTO objetcs

This patch is for .GCC.command.line sections in LTO objects to be copied
into the final objects as in the following example:

[egeyar@localhost lto]$ gcc -flto -O3 demo.c -c -g --record-gcc-command-line
[egeyar@localhost lto]$ gcc -flto -O2 demo2.c -c -g --record-gcc-command-line -DFORTIFY=2
[egeyar@localhost lto]$ gcc demo.o demo2.o -o a.out
[egeyar@localhost lto]$ readelf -p .GCC.command.line a.out

String dump of section '.GCC.command.line':
  [     0]  10.0.1 20200227 (experimental) : gcc -flto -O3 demo.c -c -g --record-gcc-command-line
  [    56]  10.0.1 20200227 (experimental) : gcc -flto -O2 demo2.c -c -g --record-gcc-command-line -DFORTIFY=2

2020-03-05  Egeyar Bagcioglu  <egeyar.bagcioglu@oracle.com>

	* simple-object.c (handle_lto_debug_sections): Name
	".GCC.command.line" among debug sections to be copied over
	from lto objects.