elf2flt: add patch to fix ld.real search logic

elf2flt: add patch to fix ld.real search logic

elf2flt contains a program called ld-elf2flt, which gets installed as
a replacement for ld, with ld renamed to ld.real. This program
therefore calls ld.real internally.

The logic to find ld.real worked fine for:

 - bin/TARGET_ALIAS-ld
 - TARGET_ALIAS/bin/ld

However, it failed badly if bin/SIMPLER_TARGET_ALIAS-ld is used, as
symlink to bin/TARGET_ALIAS-ld. For example:

$ ./output/host/bin/arm-buildroot-uclinux-uclibcgnueabi-ld
/home/thomas/buildroot/buildroot/output/host/bin/../arm-buildroot-uclinux-uclibcgnueabi/bin/ld.real: no input files

$ ./output/host/bin/arm-linux-ld
arm-linux-ld (ld-elf2flt): error trying to exec '/home/thomas/buildroot/buildroot/output/host/bin/ld.real': execvp: No such file or directory

$ ./output/host/arm-buildroot-uclinux-uclibcgnueabi/bin/ld
/home/thomas/buildroot/buildroot/output/host/arm-buildroot-uclinux-uclibcgnueabi/bin/ld.real: no input files

This commit fixes that by adding a patch that adjusts the ld-elf2flt
logic to properly cope with this situation.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>