m_getfld.patch: fix a Memory Fault using "inc" on Linux

Hi,

We noticed that inc in nmh-0.24 sometimes fails on a Memory Fault on
Linux in the m_getfld function. 

This happens when:

  1) the stdio's buffer (iob->_ptr) is at the end of the memory

  2) the end of this buffer is reached when "incing" in the middle of
a header field.

I think, but I only read the source, that this bug is still present 
in nmh-0.26.

We are running Linux 2.0.33 with these (rather old) libraries:

ldd /usr/local/nmh/bin/inc
        libgdbm.so.1 => /lib/libgdbm.so.1.7.3
        libtermcap.so.2 => /lib/libtermcap.so.2.0.8
        libc.so.5 => /lib/libc.so.5.4.44

The following patch solves this problem.

Francis Montagnac, fm(_at_)sophia(_dot_)inria(_dot_)fr, (33) 04 92 38 79 11
INRIA Sophia, 2004, rte des Lucioles, B.P.93 - 06902 Sophia Antipolis 
Cedex

m_getfld.patch
Description: m_getfld.patch