option.sh: don't use nproc (not portable)

export LBMK_THREADS=x

where x is an integer. this is already supported for
setting the number of build threads, but if not set
it uses nproc.

openbsd doesn't have nproc. default to 1 thread.

now you MUST set threads. e.g. in linux do:

export LBMK_THREADS=$(nproc)

preliminary work is being done to make lbmk run
on openbsd!

Signed-off-by: Leah Rowe <leah@libreboot.org>

config/coreboot/x220edp_8mb/target.cfg

@@ -6,3 +6,4 @@ payload_seabios="y"
 payload_memtest="y"
 grub_scan_disk="ahci"
 status="broken" # TODO: VCC3P patch
+release="n"

config/coreboot/x230edp_12mb/target.cfg

@@ -6,3 +6,4 @@ payload_seabios="y"
 payload_memtest="y"
 grub_scan_disk="ahci"
 status="broken" # TODO: VCC3P patch
+release="n"

include/option.sh

@@ -23,13 +23,14 @@ eval "$(setvars "" CONFIG_BOARD_DELL_E6400 CONFIG_HAVE_MRC CONFIG_HAVE_ME_BIN \
     CONFIG_HAVE_REFCODE_BLOB CONFIG_REFCODE_BLOB_FILE)"
 
 threads=
-set | grep LBMK_THREADS 1>/dev/null 2>/dev/null || threads=$(nproc) || :
-[ -z "$threads" ] && threads=$LBMK_THREADS
-[ -z "$threads" ] && threads=1 # LBMK_THREADS not set, and nproc failed
+set | grep LBMK_THREADS 1>/dev/null 2>/dev/null && threads="$LBMK_THREADS"
+[ -z "$threads" ] && threads=1
 
 expr "X$threads" : "X-\{0,1\}[0123456789][0123456789]*$" \
     1>/dev/null 2>/dev/null || threads=1 # user specified a non-integer
 
+export LBMK_THREADS="$threads"
+
 items()
 {
 	rval=1