bfin-xxx-gcc-4.3.1中config.status的生成及运行（2）：Shell检测
快乐虾
http://blog.csdn.net/lights_joy/
本文适用于
gcc- 4.3.1
Blackfin系列DSP
Visual Studio 2005
欢迎转载，但请保留作者信息
这段输出的代码较长，但是无非是在检测不同bash之间的一些差异，没什么实质性的内容。
cat >>$CONFIG_STATUS <</_ACEOF
## --------------------- ##
## M4sh Initialization. ##
## --------------------- ##
# Be Bourne compatible
if test -n "${ZSH_VERSION+set}" && (emulate sh) >/dev/null 2>&1; then
emulate sh
NULLCMD=:
# Zsh 3.x and 4.x performs word splitting on ${1+"$@"}, which
# is contrary to our usage. Disable this feature.
alias -g '${1+"$@"}'='"$@"'
elif test -n "${BASH_VERSION+set}" && (set -o posix) >/dev/null 2>&1; then
set -o posix
fi
DUALCASE=1; export DUALCASE # for MKS sh
# Support unset when possible.
if ( (MAIL=60; unset MAIL) || exit) >/dev/null 2>&1; then
as_unset=unset
else
as_unset=false
fi
# Work around bugs in pre-3.0 UWIN ksh.
$as_unset ENV MAIL MAILPATH
PS1='$ '
PS2='> '
PS4='+ '
# NLS nuisances.
# 动态设置一些全局变量的值为C
for as_var in /
LANG LANGUAGE LC_ADDRESS LC_ALL LC_COLLATE LC_CTYPE LC_IDENTIFICATION /
LC_MEASUREMENT LC_MESSAGES LC_MONETARY LC_NAME LC_NUMERIC LC_PAPER /
LC_TELEPHONE LC_TIME
do
if (set +x; test -z "`(eval $as_var=C; export $as_var) 2>&1`"); then
eval $as_var=C; export $as_var
else
$as_unset $as_var
fi
done
# Required to use basename.
# 测试是否支持expr命令，在cygwin下为expr
if expr a : '/(a/)' >/dev/null 2>&1; then
as_expr=expr
else
as_expr=false
fi
# 测试是否支持basename命令，在此认为支持。
if (basename /) >/dev/null 2>&1 && test "X`basename / 2>&1`" = "X/"; then
as_basename=basename
else
as_basename=false
fi
# Name of the executable.
as_me=`$as_basename "$0" ||
$as_expr X/"$0" : '.*//([^/][^/]*/)/*$' /| /
X"$0" : 'X/(///)$' /| /
X"$0" : 'X/(//)$' /| /
. : '/(./)' 2>/dev/null ||
echo X/"$0" |
sed '/^.*///([^/][^/]*/)//*$/{ s///1/; q; }
/^X///(/////)$/{ s///1/; q; }
/^X///(///).*/{ s///1/; q; }
s/.*/./; q'`
# PATH needs CR, and LINENO needs CR and PATH.
# Avoid depending upon Character Ranges .
as_cr_letters='abcdefghijklmnopqrstuvwxyz'
as_cr_LETTERS='ABCDEFGHIJKLMNOPQRSTUVWXYZ'
as_cr_Letters=$as_cr_letters$as_cr_LETTERS
as_cr_digits='0123456789'
as_cr_alnum=$as_cr_Letters$as_cr_digits
# The user is always right.
# 设置PATH_SEPARATOR变量，最后它的值为冒号：
if test "${PATH_SEPARATOR+set}" != set; then
echo "#! /bin/sh" >conf$$.sh
echo "exit 0" >>conf$$.sh
chmod +x conf$$.sh
if (PATH="/nonexistent;."; conf$$.sh) >/dev/null 2>&1; then
PATH_SEPARATOR=';'
else
PATH_SEPARATOR=:
fi
rm -f conf$$.sh
fi
as_lineno_1=$LINENO
as_lineno_2=$LINENO
as_lineno_3=`(expr $as_lineno_1 + 1) 2>/dev/null`
test "x$as_lineno_1" != "x$as_lineno_2" &&
test "x$as_lineno_3" = "x$as_lineno_2" || {
# Find who we are. Look in the path if we contain no path at all
# relative or not.
case $ 0 in
*[///]* ) as_myself=$0 ;;
*) as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
for as_dir in $PATH
do
IFS=$as_save_IFS
test -z "$as_dir" && as_dir=.
test -r "$as_dir/$0" && as_myself=$as_dir/$0 && break
done
;;
Esac
# We did not find ourselves, most probably we were run as `sh COMMAND'
# in which case we are not to be found in the path.
if test "x$as_myself" = x; then
as_myself=$0
fi
if test ! -f "$as_myself"; then
{ { echo "$as_me:$LINENO: error: cannot find myself; rerun with an absolute path" >&5
echo "$as_me: error: cannot find myself; rerun with an absolute path" >&2;}
{ (exit 1); exit 1; }; }
fi
case $CONFIG_SHELL in
'')
as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
for as_dir in /bin$PATH_SEPARATOR/usr/bin$PATH_SEPARATOR$PATH
do
IFS=$as_save_IFS
test -z "$as_dir" && as_dir=.
for as_base in sh bash ksh sh5; do
case $as_dir in
/*)
if ("$as_dir/$as_base" -c '
as_lineno_1=$LINENO
as_lineno_2=$LINENO
as_lineno_3=`(expr $as_lineno_1 + 1) 2>/dev/null`
test "x$as_lineno_1" != "x$as_lineno_2" &&
test "x$as_lineno_3" = "x$as_lineno_2" ') 2>/dev/null; then
$as_unset BASH_ENV || test "${BASH_ENV+set}" != set || { BASH_ENV=; export BASH_ENV; }
$as_unset ENV || test "${ENV+set}" != set || { ENV=; export ENV; }
CONFIG_SHELL=$as_dir/$as_base
export CONFIG_SHELL
exec "$CONFIG_SHELL" "$0" ${1+"$@"}
fi;;
esac
done
done
;;
esac
# Create $as_me.lineno as a copy of $as_myself, but with $LINENO
# uniformly replaced by the line number. The first 'sed' inserts a
# line-number line before each line; the second 'sed' does the real
# work. The second script uses 'N' to pair each line-number line
# with the numbered line, and appends trailing '-' during
# substitution so that $LINENO is not a special case at line end.
# (Raja R Harinath suggested sed '=', and Paul Eggert wrote the
# second 'sed' script. Blame Lee E. McMahon for sed's syntax. :-)
sed '=' <$as_myself |
sed '
N
s,$,-,
: loop
s,^/(['$as_cr_digits']*/)/(.*/)[$]LINENO/([^'$as_cr_alnum'_]/),/1/2/1/3,
t loop
s,-$,,
s,^['$as_cr_digits']*/n,,
' >$as_me.lineno &&
chmod +x $as_me.lineno ||
{ { echo "$as_me:$LINENO: error: cannot create $as_me.lineno; rerun with a POSIX shell" >&5
echo "$as_me: error: cannot create $as_me.lineno; rerun with a POSIX shell" >&2;}
{ (exit 1); exit 1; }; }
# Don't try to exec as it changes $[0], causing all sort of problems
# (the dirname of $[0] is not the place where we might find the
# original and so on. Autoconf is especially sensible to this).
. ./$as_me.lineno
# Exit status is that of the last command.
exit
}
case `echo "testing/c"; echo 1,2,3`,`echo -n testing; echo 1,2,3` in
*c*,-n*) ECHO_N= ECHO_C='
' ECHO_T=' ' ;;
*c*,* ) ECHO_N=-n ECHO_C= ECHO_T= ;;
*) ECHO_N= ECHO_C='/c' ECHO_T= ;;
esac
if expr a : '/(a/)' >/dev/null 2>&1; then
as_expr=expr
else
as_expr=false
fi
rm -f conf$$ conf$$.exe conf$$.file
echo >conf$$.file
if ln -s conf$$.file conf$$ 2>/dev/null; then
# We could just check for DJGPP; but this test a) works b) is more generic
# and c) will remain valid once DJGPP supports symlinks (DJGPP 2.04).
if test -f conf$$.exe; then
# Don't use ln at all; we don't have any links
as_ln_s='cp -p'
else
as_ln_s='ln -s'
fi
elif ln conf$$.file conf$$ 2>/dev/null; then
as_ln_s=ln
else
as_ln_s='cp -p'
fi
rm -f conf$$ conf$$.exe conf$$.file
if mkdir -p . 2>/dev/null; then
as_mkdir_p=:
else
test -d ./-p && rmdir ./-p
as_mkdir_p=false
fi
as_executable_p="test -f"
# Sed expression to map a string onto a valid CPP name.
as_tr_cpp="eval sed 'y%*$as_cr_letters%P$as_cr_LETTERS%;s%[^_$as_cr_alnum]%_%g'"
# Sed expression to map a string onto a valid variable name.
as_tr_sh="eval sed 'y%*+%pp%;s%[^_$as_cr_alnum]%_%g'"
# IFS
# We need space, tab and new line, in precisely that order.
as_nl='
'
IFS=" $as_nl"
# CDPATH.
$as_unset CDPATH
exec 6>&1
# Open the log real soon, to keep /$[0] and so on meaningful, and to
# report actual input values of CONFIG_FILES etc. instead of their
# values after options handling. Logging --version etc. is OK.
exec 5>>config.log
{
echo
sed 'h;s/./-/g;s/^.../## /;s/...$/ ##/;p;x;p;x' <<_ASBOX
## Running $as_me. ##
_ASBOX
} >&5
cat >&5 <<_CSEOF
This file was extended by $as_me, which was
generated by GNU Autoconf 2.59. Invocation command line was
CONFIG_FILES = $CONFIG_FILES
CONFIG_HEADERS = $CONFIG_HEADERS
CONFIG_LINKS = $CONFIG_LINKS
CONFIG_COMMANDS = $CONFIG_COMMANDS
$ $0 $@
_CSEOF
echo "on `(hostname || uname -n) 2>/dev/null | sed 1q`" >&5
echo >&5
_ACEOF
在这段脚本的末尾，输出了一段信息到config.log文件中，但是对几个变量进行了替换，所以最终输出到config.log中的信息就变成了：
This file contains any messages produced by compilers while
running configure, to aid debugging if configure makes a mistake.
It was created by configure, which was
generated by GNU Autoconf 2.59. Invocation command line was
$ ./configure --target=bfin-gnu-linux target_alias=bfin-gnu-linux --no-create --no-recursion
参考资料
bfin-gcc-4.3.1中config.h的生成( 2008-8-5 )
bfin-xxx-gcc-4.3.1中config.status的生成及运行（1）：输出注释( 2008-8-5 )