Don't clear BUILD_CFLAGS and BUILD_LDFLAGS when cross-compiling

Signed-off-by: Michael Forney <forney@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
fix build with configure --disable-uuid --disable-blkid --enable-profile

We need to make sure PROFILED_LIBUUID and PROFILED_LIBBLKID are
defined when we are using the system uuid and blkid libraries.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
misc: zero s_jnl_blocks when adding journal online or removing external journal

Erase s_jnl_blocks when removing an external journal, or adding an
internal journal online.  We can't add the backup for the internal
journal because we have no good way to get the indirect block or ETB
addresses, so the best we can do is hope that the user runs e2fsck,
which will correct that.  We are motivated to erase during external
journal removal to state emphatically that there's no journal.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reported-by: thomas_reardon@hotmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
mke2fs: don't depend on <linux/version.h>

Define the KERNEL_VERSION macro explicitly instead of using
<linux/version.h>, since it's not available when using dietlibc.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
configure: disable uuidd by default if libuuid is disabled

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
misc: fix build breakage with configure --disable-uuidd --enable-profile

Signed-off-by: Theodore Ts'o <tytso@mit.edu>