Unable to compile GDB with expat for use with remote debugging

Question

I have been trying to compile a copy of GDB on 64 bit X86 Ubuntu for use with remote debugging of an ARM device. This means compiling GDB using expat; GDB uses XML parsing when connecting to a remote debugger. Here are some of the things I've tried, and the results.

Compile with just --with-expat

./configure --target=arm-none-eabi --with-expat 
make

....
checking whether to use expat... yes
checking for libexpat... (cached) no
configure: error: expat is missing or unusable
Makefile:9125: recipe for target 'configure-gdb' failed
....

Compile with --with-libexpat-prefix

ls -alg /usr/local/lib/*expat*
-rw-r--r-- 1 root 999128 Mar 20 23:55 /usr/local/lib/libexpat.a
-rwxr-xr-x 1 root    942 Mar 20 23:55 /usr/local/lib/libexpat.la
lrwxrwxrwx 1 root     17 Mar 20 23:55 /usr/local/lib/libexpat.so -> libexpat.so.1.6.0
lrwxrwxrwx 1 root     17 Mar 20 23:55 /usr/local/lib/libexpat.so.1 -> libexpat.so.1.6.0
-rwxr-xr-x 1 root 534224 Mar 20 23:55 /usr/local/lib/libexpat.so.1.6.0

./configure --target=arm-none-eabi --with-expat --with-libexpat-prefix=/usr/local/lib
make

....
checking whether to use expat... yes
checking for libexpat... (cached) no
configure: error: expat is missing or unusable
Makefile:9125: recipe for target 'configure-gdb' failed
....

I've tried to install expat in every way I can think of. The above library binaries are from a local compile of expat with make install; I've also done:

apt-get install libexpat1-dev
apt-get install expat

Both are already the newest version. Same results as above; I can only compile if I omit --with-expat and --with-libexpat-prefix.

Suggestions welcome. How can I find out more about the failure - how can I figure out how/where the make process is failing to find/approve of expat?

Fellow travellers (but I found no working answers here):

gdb building with expat

http://comments.gmane.org/gmane.comp.gdb.devel/29306

gdb remote cross debugging fails with "Remote 'g' packet reply is too long"

Answer 1

I made two changes that got it working for me.

First, my ./configure command was subtly wrong. Instead of

./configure --target=arm-none-eabi --with-expat --with-libexpat-prefix=/usr/local/lib

it should be

./configure --target=arm-none-eabi --with-expat --with-libexpat-prefix=/usr/local/

because the prefix is supposed to be above both include and lib. From the configure file:

--with-expat            include expat support (auto/yes/no)
--with-libexpat-prefix[=DIR]  search for libexpat in DIR/include and DIR/lib

But I'm not sure that was the real solution. I was still getting the same compile error until I accidentally started the compile from the gdb directory in the root directory for gdb. Let me be totally explicit:

root@scallion:~/gdb-arm-build/gdb-7.11# ls -alg
total 5016
drwxr-xr-x 16 root    4096 Mar 21 23:48 .
drwxr-xr-x  3 root    4096 Mar 20 16:54 ..
drwxr-xr-x  7 root   20480 Mar 21 23:48 bfd
-rw-rw-rw-  1  200  492650 Feb 24 01:55 ChangeLog
-rwxrwxrwx  1  200    7333 Feb 19  2015 compile
drwxr-xr-x  2 root    4096 Mar 20 16:54 config
-rwxrwxrwx  1  200   43614 Feb  9 19:19 config.guess
-rw-rw-rw-  1  200   25713 Feb  9 19:19 config-ml.in
-rwxrwxrwx  1  200   14916 Jun 11  2014 config.rpath
-rwxr-xr-x  1 root   31637 Mar 21 23:48 config.status
-rwxrwxrwx  1  200   36139 Feb  9 19:19 config.sub
-rwxrwxrwx  1  200  486119 Feb 24 01:55 configure
-rw-rw-rw-  1  200  113771 Feb 24 01:59 configure.ac
-rw-rw-rw-  1  200   18002 Jun 11  2014 COPYING
-rw-rw-rw-  1  200   35147 Jun 11  2014 COPYING3
-rw-rw-rw-  1  200    7639 Jun 11  2014 COPYING3.LIB
-rw-rw-rw-  1  200   25291 Jun 11  2014 COPYING.LIB
drwxr-xr-x  2 root    4096 Mar 20 16:54 cpu
-rwxrwxrwx  1  200   22464 Feb 19  2015 depcomp
-rw-r--r--  1  200    1887 Feb 24 01:59 djunpack.bat
drwxr-xr-x  2 root    4096 Mar 21 23:49 etc
drwxr-xr-x 27 root   36864 Mar 21 23:51 gdb **<<<<<<<< Here**
drwxr-xr-x 12 root    4096 Mar 20 16:54 include
-rwxrwxrwx  1  200   14675 Feb 19  2015 install-sh
drwxr-xr-x  2 root    4096 Mar 21 23:48 intl
drwxr-xr-x  4 root    4096 Mar 21 23:49 libdecnumber
drwxr-xr-x  4 root   12288 Mar 21 23:48 libiberty
-rw-rw-rw-  1  200  263820 Feb  9 19:19 libtool.m4
-rw-rw-rw-  1  200    1768 Jun 11  2014 ltgcc.m4
-rw-rw-rw-  1  200  249723 Jun 11  2014 ltmain.sh
-rw-rw-rw-  1  200    6126 Jun 11  2014 lt~obsolete.m4
-rw-rw-rw-  1  200   11950 Jun 11  2014 ltoptions.m4
-rw-rw-rw-  1  200    4372 Jun 11  2014 ltsugar.m4
-rw-rw-rw-  1  200     703 Jun 11  2014 ltversion.m4
-rw-rw-rw-  1  200    3909 Feb 19  2015 MAINTAINERS
-rw-r--r--  1 root  414118 Mar 21 23:48 Makefile
-rw-rw-rw-  1  200   30110 Feb  9 19:19 Makefile.def
-rw-rw-rw-  1  200 1719859 Feb 24 01:57 Makefile.in
-rw-rw-rw-  1  200   69660 Feb 24 01:55 Makefile.tpl
-rw-r--r--  1  200  736309 Feb 24 01:59 md5.sum
-rwxrwxrwx  1  200    6872 Feb 19  2015 missing
-rwxrwxrwx  1  200    2179 Jun 11  2014 mkdep
-rwxrwxrwx  1  200    3538 Feb 19  2015 mkinstalldirs
-rwxrwxrwx  1  200    2636 Feb 19  2015 move-if-change
drwxr-xr-x  5 root   12288 Mar 21 23:49 opcodes
drwxr-xr-x  7 root    4096 Mar 21 23:49 readline
-rw-rw-rw-  1  200    1719 Jun 11  2014 README
-rw-rw-rw-  1  200     961 Jun 11  2014 README-maintainer-mode
-rw-r--r--  1 root      13 Mar 21 23:48 serdep.tmp
drwxr-xr-x 33 root    4096 Mar 21 23:49 sim
-rwxrwxrwx  1  200    9150 Feb  9 19:19 src-release.sh
-rwxrwxrwx  1  200    2265 Jun 11  2014 symlink-tree
drwxr-xr-x  2 root    4096 Mar 20 16:54 texinfo
-rwxrwxrwx  1  200    6421 Feb 19  2015 ylwrap
drwxr-xr-x 14 root    4096 Mar 21 23:48 zlib

Not until I ran make from the directory gdb-arm-build/gdb-7.11/gdb did it succeed for me. Using the resulting gdb binary, I can now connect to the target, stop, start, look at registers, symbols, etc. If I find there's anything deficient about my compile I will follow up, but for now I'm good.

I don't know what I'm not understanding here, so if someone can shed light on what mistake I was making, I'd appreciate it.