script: Make the get_default_envs.sh script working with newest u-boot

This commit fixes several issues:

- After moving env related code to ./env directory the env_common.o file
is no longer present in the system (has been replaced with built-in.o).

- Use ${OBJCOPY} if available, fallback to system default's objcopy if not
present.

- Extend the script to accept different build directory than current one.
It is extremely handy with OE usage, where source code is separated from
build.

Signed-off-by: Lukasz Majewski <lukma@denx.de>
Tested-by: Alex Kiernan <alex.kiernan@gmail.com>

scripts/get_default_envs.sh

@@ -6,16 +6,24 @@
 #
 
 # This file extracts default envs from built u-boot
-# usage: get_default_envs.sh > u-boot-env-default.txt
+# usage: get_default_envs.sh [build dir] > u-boot-env-default.txt
 set -ue
 
-ENV_OBJ_FILE="env_common.o"
+: "${OBJCOPY:=${CROSS_COMPILE:-}objcopy}"
+
+ENV_OBJ_FILE="built-in.o"
 ENV_OBJ_FILE_COPY="copy_${ENV_OBJ_FILE}"
 
 echoerr() { echo "$@" 1>&2; }
 
-path=$(readlink -f $0)
-env_obj_file_path=$(find ${path%/scripts*} -not -path "*/spl/*" \
+if [ "$#" -eq 1 ]; then
+    path=${1}
+else
+    path=$(readlink -f $0)
+    path=${path%/scripts*}
+fi
+
+env_obj_file_path=$(find ${path} -path "*/env/*" -not -path "*/spl/*" \
 			 -name "${ENV_OBJ_FILE}")
 [ -z "${env_obj_file_path}" ] && \
     { echoerr "File '${ENV_OBJ_FILE}' not found!"; exit 1; }
@@ -23,8 +31,9 @@ env_obj_file_path=$(find ${path%/scripts*} -not -path "*/spl/*" \
 cp ${env_obj_file_path} ${ENV_OBJ_FILE_COPY}
 
 # NOTE: objcopy saves its output to file passed in
-# (copy_env_common.o in this case)
-objcopy -O binary -j ".rodata.default_environment" ${ENV_OBJ_FILE_COPY}
+# (copy_${ENV_OBJ_FILE} in this case)
+
+${OBJCOPY} -O binary -j ".rodata.default_environment" ${ENV_OBJ_FILE_COPY}
 
 # Replace default '\0' with '\n' and sort entries
 tr '\0' '\n' < ${ENV_OBJ_FILE_COPY} | sort -u