Fix OS X crossbuilds for arm

- Fixed missing variable interpolation because of single quotes
 - Replaced /bin/sh in gen_uEnv.txt.sh with /usr/bin/env bash as the default
   echo doesn't support '-n'
 - Fixed some whitespace errors
 - A succesful build requires for now to skip the gold linker on OSX.

Change-Id: Id09bf52f45252026e3a58b74e8448ea24a0dab12

releasetools/arm_sdimage.sh

@@ -79,7 +79,7 @@ HOME_START=$(($USR_START + $USR_SIZE))
 case $(uname -s) in
 Darwin)
 	MKFS_VFAT_CMD=newfs_msdos
-	MKFS_VFAT_OPTS='-h 64 -u 32 -S 512 -s ${FAT_SIZE} -o 0'
+	MKFS_VFAT_OPTS="-h 64 -u 32 -S 512 -s ${FAT_SIZE} -o 0"
 ;;
 FreeBSD)
 	MKFS_VFAT_CMD=newfs_msdos

releasetools/gen_uEnv.txt.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/usr/bin/env bash
 
 #generate a u-boot u-env.
 list="0x80200000 kernel.bin
@@ -29,27 +29,27 @@ HZ=1000
 
 while getopts "c:v:h:p:n?" c
 do
-        case "$c" in
-        \?)
-                echo "Usage: $0 [-p netboot_prefix] -n [-c consoletty] [-v level] " >&2
-                exit 1
-        	;;
-        n)
+	case "$c" in
+	\?)
+		echo "Usage: $0 [-p netboot_prefix] -n [-c consoletty] [-v level] " >&2
+		exit 1
+		;;
+	n)
 		# genrate netbooting uEnv.txt
-                BOOT="netbootcmd"
-                NETBOOT="yes"
+		BOOT="netbootcmd"
+		NETBOOT="yes"
 		;;
-        p)
-                NETBOOT_PREFIX=$OPTARG
+	p)
+		NETBOOT_PREFIX=$OPTARG
 		;;
-        c)
-                CONSOLE=$OPTARG
+	c)
+		CONSOLE=$OPTARG
 		;;
-        v)
-                VERBOSE=$OPTARG
+	v)
+		VERBOSE=$OPTARG
 		;;
-        h)
-                # system hz
+	h)
+		# system hz
 		HZ=$OPTARG
 		;;
 	esac