bootstrap/gcc.bst: Fix confusion of binaries used for target and build.

When not cross-compiling, the tools have the same names, and only
the first one in PATH is used. Intermediate binaries intended
to run during the build might get linked to the target system
rather than the current system.
13 jobs for valentindavid/glibc-2-29 in 917 minutes and 40 seconds
Status Job ID Name Coverage
  Flatpak
passed #228580074
aarch64
app_aarch64

12:18:44

passed #228513900
armhf
app_arm

09:13:26

passed #228513914
x86_64 cache_i686
app_i686

10:32:49

passed #228513933
x86_64 cache_x86_64
app_x86_64

11:49:37

failed #228195578
aarch64
app_aarch64

09:08:25

failed #228195579
armhf
app_arm

06:32:06

failed #228195577
cache_i686 x86_64
app_i686

06:16:23

failed #228195576
cache_x86_64 x86_64
app_x86_64

07:03:35

 
  Vm
manual #228195582
aarch64 allowed to fail manual
minimal_systemd_vm_aarch64
passed #228920993
armhf
minimal_systemd_vm_arm

00:39:14

passed #228195581
cache_i686 x86_64
minimal_systemd_vm_i686

00:02:19

passed #228195580
cache_x86_64 x86_64
minimal_systemd_vm_x86_64

00:02:18

canceled #228195583
armhf
minimal_systemd_vm_arm

02:14:58