buildgcc: Rename quit() to exit_handler()

"quit" is a signal name. The FreeBSD `sh` interprets

    trap quit 1 2 3 15

as command to reset all the respective signal handlers, instead
of setting quit() as handler.

Change-Id: I69b813ab583f15a9dd89a115f7aea66d966f981b
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/20391
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

util/crossgcc/buildgcc

@@ -431,7 +431,7 @@ build()
 	fi
 }
 
-quit()
+exit_handler()
 {
 	printf "${NC}Stop\n"
 	exit 1
@@ -807,7 +807,7 @@ print_supported() {
 	esac
 }
 
-trap quit 1 2 3 15
+trap exit_handler 1 2 3 15
 
 # Look if we have getopt. If not, build it.
 export PATH=$PATH:.