Share gcc work directories

Share gcc work directories

This patched is derived from Richard, make gcc use the shared source
directory during the different building:

1) Make gcc-cross, gcc-cross-initial, gcc-cross-intermediate and
   gcc-runtime share the same source directory.

2) The source directory is ${TMPDIR}/work-shared/gcc-${PV}, for example:
   tmp/work-shared/gcc-4.5.1

3) Fix do_clean to clean the shared source directory and stamps

4) gcc uses sed and creates config files against ${S} which means the
   directory should not be shared. Change the way to make it work:

   * The configure option --with-headers=${STAGING_DIR_TARGET}${SYSTEMHEADERS}
     can replace the sed command, see the code in configure:

        if test "x$with_headers" != x; then
          glibc_header_dir=$with_headers

    This has the same effect as the sed command:

    sed -i 's:^\([  ]*\)glibc_header_dir=\"${with_build_sysroot}/usr/include\": ...

    so add the --with-headers=${STAGING_DIR_TARGET}${SYSTEMHEADERS} to
    gcc-configure-cross.inc( not add to gcc-configure-common.inc, since
    not all the gcc building need this, the one which has its own do_configure
    doesn't need it).

   * Move t-oe from ${T} to ${B}/gcc, so that the patched Makefile.in
     can read it easily, please see the commit for gcc-4.5.1 and
     gcc-4.6.0.

   * Use the defaults.h in ${B}/gcc instead of ${S}/gcc, and the patched
     configure.ac(configure) can read it correctly, please see the
     commit for gcc-4.5.1 and gcc-4.6.0.

   * The gcc-crosssdk.inc used sed to edit ${S}/config/*/linux*.h
     to change the GLIBC_DYNAMIC_LINKER, which made the source
     incompatible. To make the source compatible:
     - Use:
	 sed -i ${S}/gcc/config/*/linux*.h -e \
		's#\(GLIBC_DYNAMIC_LINKER[^ ]*\)\( *"/lib.*\)#\1 SYSTEMLIBS_DIR\2#'

	so entries in the files that look like:
	#define GLIBC_DYNAMIC_LINKER64 "/lib64/ld-linux-x86-64.so.2"
	would become
	#define GLIBC_DYNAMIC_LINKER64 SYSTEMLIBS_DIR"/ld-linux-x86-64.so.2"
	and we define SYSTEMLIBS_DIR in defaults.h.

	NOTE:
	#define GLIBC_DYNAMIC_LINKER64 (SYSTEMLIBS_DIR "/ld-linux-x86-64.so.2")
	doesn't work in in the following define:
	#define LINUX_DYNAMIC_LINKER \
  		CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER, UCLIBC_DYNAMIC_LINKER)
	so use
	#define GLIBC_DYNAMIC_LINKER64 SYSTEMLIBS_DIR"/ld-linux-x86-64.so.2"

5) Add do_configure_prepend to gcc-configure-common.inc and remove the
   one in gcc-crosssdk.inc, this makes it easy to share the source,
   otherwise we need do extra changes in gcc-configure-sdk.inc.

6) Use "cat > file <_EOF" to replace the "echo > file"

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>