diff -upr mmh-0.2.orig/sbr/m_getfld.c mmh-0.2/sbr/m_getfld.c
--- mmh-0.2.orig/sbr/m_getfld.c	2015-12-21 03:36:00.060760463 +0100
+++ mmh-0.2/sbr/m_getfld.c	2015-12-21 03:38:04.080205306 +0100
@@ -149,26 +149,81 @@ static int edelimlen;
 
 static int (*eom_action)(int) = NULL;
 
-#ifdef _FSTDIO
-# define _ptr _p  /* Gag   */
-# define _cnt _r  /* Retch */
-# define _filbuf __srget  /* Puke  */
-# define DEFINED__FILBUF_TO_SOMETHING_SPECIFIC
-#endif
-
-#ifndef DEFINED__FILBUF_TO_SOMETHING_SPECIFIC
-extern int  _filbuf(FILE*);
-#endif
+/*
+** This replaces the old approach, which included direct access to
+** stdio internals.  It uses one fread() to load a buffer that we
+** manage.
+*/
+#define MSG_INPUT_SIZE 8192
+static struct m_getfld_buffer {
+	unsigned char msg_buf[2 * MSG_INPUT_SIZE];
+	unsigned char *readpos;
+	unsigned char *end;  /* One past the last character read in. */
+} m;
+
+static void
+setup_buffer(FILE *iob, struct m_getfld_buffer *m)
+{
+	/*
+	** Rely on Restrictions that m_getfld() calls on different file
+	** streams are not interleaved, and no other file stream read
+	** methods are used.  And, the first call to m_getfld (), etc., on
+	** a stream always reads at least 1 byte.
+	** I don't think it's necessary to use ftello() because we just
+	** need to determine whether the current offset is 0 or not.
+	*/
+	if (ftell(iob) == 0) {
+		/* A new file stream, so reset the buffer state. */
+		m->readpos = m->end = m->msg_buf;
+	}
+}
+
+static size_t
+read_more(struct m_getfld_buffer *m, FILE *iob)
+{
+	size_t num_read;
+
+	/* Move any leftover at the end of buf to the beginning. */
+	if (m->end > m->readpos) {
+		memmove(m->msg_buf, m->readpos, m->end - m->readpos);
+	}
+	m->readpos = m->msg_buf + (m->end - m->readpos);
+	num_read = fread(m->readpos, 1, MSG_INPUT_SIZE, iob);
+	m->end = m->readpos + num_read;
 
+	return num_read;
+}
+
+static int
+Getc(FILE *iob)
+{
+	if (m.end - m.readpos < 1) {
+		if (read_more(&m, iob) == 0) {
+			/*
+			**  Pretend that we read a character.
+			** That's what stdio does.
+			*/
+			++m.readpos;
+			return EOF;
+		}
+	}
+	return (m.readpos < m.end) ? *m.readpos++ : EOF;
+}
+
+static int
+Ungetc(int c, FILE *iob)
+{
+	return (m.readpos == m.msg_buf) ? EOF : (*--m.readpos = c);
+}
 
 int
 m_getfld(int state, unsigned char *name, unsigned char *buf,
 	int bufsz, FILE *iob)
 {
 	unsigned char  *bp, *cp, *ep, *sp;
-	int cnt, c, i, j;
+	int cnt, c, i, j, k;
 
-	if ((c = getc(iob)) < 0) {
+	if ((c = Getc(iob)) < 0) {
 		msg_count = 0;
 		*buf = 0;
 		return FILEEOF;
@@ -176,10 +231,10 @@ m_getfld(int state, unsigned char *name,
 	if (eom(c, iob)) {
 		if (! eom_action) {
 			/* flush null messages */
-			while ((c = getc(iob)) >= 0 && eom(c, iob))
+			while ((c = Getc(iob)) >= 0 && eom(c, iob))
 				;
 			if (c >= 0)
-				ungetc(c, iob);
+				Ungetc(c, iob);
 		}
 		msg_count = 0;
 		*buf = 0;
@@ -192,16 +247,16 @@ m_getfld(int state, unsigned char *name,
 	case FLD:
 		if (c == '\n' || c == '-') {
 			/* we hit the header/body separator */
-			while (c != '\n' && (c = getc(iob)) >= 0)
+			while (c != '\n' && (c = Getc(iob)) >= 0)
 				;
 
-			if (c < 0 || (c = getc(iob)) < 0 || eom(c, iob)) {
+			if (c < 0 || (c = Getc(iob)) < 0 || eom(c, iob)) {
 				if (!eom_action) {
 					/* flush null messages */
-					while ((c = getc(iob)) >= 0 && eom(c, iob))
+					while ((c = Getc(iob)) >= 0 && eom(c, iob))
 						;
 					if (c >= 0)
-						ungetc(c, iob);
+						Ungetc(c, iob);
 				}
 				msg_count = 0;
 				*buf = 0;
@@ -218,47 +273,28 @@ m_getfld(int state, unsigned char *name,
 		cp = name;
 		i = NAMESZ - 1;
 		for (;;) {
-#ifdef LINUX_STDIO
-			bp = sp = (unsigned char *) iob->_IO_read_ptr - 1;
-			j = (cnt = ((long) iob->_IO_read_end -
-				(long) iob->_IO_read_ptr)  + 1) < i ? cnt : i;
-#elif defined(__DragonFly__)
-			bp = sp = (unsigned char *) ((struct __FILE_public *)iob)->_p - 1;
-			j = (cnt = ((struct __FILE_public *)iob)->_r+1) < i ? cnt : i;
-#else
-			bp = sp = (unsigned char *) iob->_ptr - 1;
-			j = (cnt = iob->_cnt+1) < i ? cnt : i;
-#endif
+			/* Store current pos, ungetting the last char. */
+			bp = sp = (unsigned char *) m.readpos - 1;
+			j = ((cnt = m.end - m.readpos + 1) < i) ? cnt : i;
+
 			while (--j >= 0 && (c = *bp++) != ':' && c != '\n')
 				*cp++ = c;
 
 			j = bp - sp;
 			if ((cnt -= j) <= 0) {
-#ifdef LINUX_STDIO
-				iob->_IO_read_ptr = iob->_IO_read_end;
-				if (__underflow(iob) == EOF) {
-#elif defined(__DragonFly__)
-				if (__srget(iob) == EOF) {
-#else
-				if (_filbuf(iob) == EOF) {
-#endif
+				/*
+				** Used to explicitly force refill of the
+				** buffer here, but Getc() will do that
+				** if necessary.
+				*/
+				if (Getc (iob) == EOF) {
 					*cp = *buf = 0;
 					advise(NULL, "eof encountered in field \"%s\"", name);
 					return FMTERR;
 				}
-#ifdef LINUX_STDIO
-				iob->_IO_read_ptr++; /* NOT automatic in __underflow()! */
-#endif
 			} else {
-#ifdef LINUX_STDIO
-				iob->_IO_read_ptr = bp + 1;
-#elif defined(__DragonFly__)
-				((struct __FILE_public *)iob)->_p = bp + 1;
-				((struct __FILE_public *)iob)->_r = cnt - 1;
-#else
-				iob->_ptr = bp + 1;
-				iob->_cnt = cnt - 1;
-#endif
+				/* Restore the current offset. */
+				m.readpos = bp + 1;
 			}
 			if (c == ':')
 				break;
@@ -312,7 +348,14 @@ m_getfld(int state, unsigned char *name,
 				** that should be harmless enough, right?
 				** This is a corrupt message anyway.
 				*/
-				fseek(iob, ftell(iob) - 2, SEEK_SET);
+				/* emulates:  fseek(iob, ftell(iob) -(-2 + cnt + 1), SEEK_SET) */
+				m.readpos += cnt - 1;
+				/*
+				** Reset file stream position so caller,
+				** e.g., get_content, can use ftell(), etc.
+				*/
+				fseek(iob, -cnt - 1, SEEK_CUR);
+
 				return BODY;
 			}
 			if ((i -= j) <= 0) {
@@ -336,16 +379,9 @@ m_getfld(int state, unsigned char *name,
 		*/
 		cp = buf; i = bufsz-1;
 		for (;;) {
-#ifdef LINUX_STDIO
-			cnt = (long) iob->_IO_read_end - (long) iob->_IO_read_ptr;
-			bp = (unsigned char *) --iob->_IO_read_ptr;
-#elif defined(__DragonFly__)
-			cnt = ((struct __FILE_public *)iob)->_r++;
-			bp = (unsigned char *) --((struct __FILE_public *)iob)->_p;
-#else
-			cnt = iob->_cnt++;
-			bp = (unsigned char *) --iob->_ptr;
-#endif
+			/* Set and save the current pos and update cnt. */
+			cnt = m.end - m.readpos;
+			bp = --m.readpos;
 			c = cnt < i ? cnt : i;
 			while ((ep = locc( c, bp, '\n' ))) {
 				/*
@@ -353,21 +389,14 @@ m_getfld(int state, unsigned char *name,
 				** return.
 				*/
 				if ((j = *++ep) != ' ' && j != '\t') {
-#ifdef LINUX_STDIO
-					j = ep - (unsigned char *) iob->_IO_read_ptr;
-					memcpy(cp, iob->_IO_read_ptr, j);
-					iob->_IO_read_ptr = ep;
-#elif defined(__DragonFly__)
-					j = ep - (unsigned char *) ((struct __FILE_public *)iob)->_p;
-					memcpy(cp, ((struct __FILE_public *)iob)->_p, j);
-					((struct __FILE_public *)iob)->_p = ep;
-					((struct __FILE_public *)iob)->_r -= j;
-#else
-					j = ep - (unsigned char *) iob->_ptr;
-					memcpy(cp, iob->_ptr, j);
-					iob->_ptr = ep;
-					iob->_cnt -= j;
-#endif
+					/*
+					** Save the text and update the
+					** current position.
+					*/
+					j = ep - m.readpos;
+					memcpy (cp, m.readpos, j);
+					m.readpos = ep;
+
 					cp += j;
 					state = FLD;
 					goto finish;
@@ -379,64 +408,33 @@ m_getfld(int state, unsigned char *name,
 			** end of input or dest buffer - copy what
 			** we've found.
 			*/
-#ifdef LINUX_STDIO
-			c += bp - (unsigned char *) iob->_IO_read_ptr;
-			memcpy(cp, iob->_IO_read_ptr, c);
-#elif defined(__DragonFly__)
-			c += bp - (unsigned char *) ((struct __FILE_public *)iob)->_p;
-			memcpy(cp, ((struct __FILE_public *)iob)->_p, c);
-#else
-			c += bp - (unsigned char *) iob->_ptr;
-			memcpy(cp, iob->_ptr, c);
-#endif
-			i -= c;
-			cp += c;
+			c += bp - m.readpos;
+			for (k = 0; k < c; ++k, --i) {
+				*cp++ = Getc (iob);
+			}
 			if (i <= 0) {
 				/* the dest buffer is full */
-#ifdef LINUX_STDIO
-				iob->_IO_read_ptr += c;
-#elif defined(__DragonFly__)
-				((struct __FILE_public *)iob)->_r -= c;
-				((struct __FILE_public *)iob)->_p += c;
-#else
-				iob->_cnt -= c;
-				iob->_ptr += c;
-#endif
-				state = FLDPLUS;
 				break;
 			}
 			/*
 			** There's one character left in the input
-			** buffer.  Copy it & fill the buffer.
-			** If the last char was a newline and the
-			** next char is not whitespace, this is
-			** the end of the field.  Otherwise loop.
+			** buffer.  Copy it & fill the buffer (that
+			** fill used to be explicit, but now Getc()
+			** does it). If the last char was a newline
+			** and the next char is not whitespace, this
+			** is the end of the field.  Otherwise loop.
 			*/
 			--i;
-#ifdef LINUX_STDIO
-			*cp++ = j = *(iob->_IO_read_ptr + c);
-			iob->_IO_read_ptr = iob->_IO_read_end;
-			c = __underflow(iob);
-			iob->_IO_read_ptr++;  /* NOT automatic! */
-#elif defined(__DragonFly__)
-			*cp++ =j = *(((struct __FILE_public *)iob)->_p + c);
-			c = __srget(iob);
-#else
-			*cp++ = j = *(iob->_ptr + c);
-			c = _filbuf(iob);
-#endif
+			*cp++ = j = Getc(iob);
+			c = Getc(iob);
 			if (c == EOF || ((j == '\0' || j == '\n')
 					&& c != ' ' && c != '\t')) {
 				if (c != EOF) {
-#ifdef LINUX_STDIO
-					--iob->_IO_read_ptr;
-#elif defined(__DragonFly__)
-					--((struct __FILE_public *)iob)->_p;
-					++((struct __FILE_public *)iob)->_r;
-#else
-					--iob->_ptr;
-					++iob->_cnt;
-#endif
+					/*
+					** Put the character back for
+					** the next call.
+					*/
+					--m.readpos;
 				}
 				state = FLD;
 				break;
@@ -454,17 +452,10 @@ m_getfld(int state, unsigned char *name,
 		** don't add an eos.
 		*/
 		i = (bufsz < 0) ? -bufsz : bufsz-1;
-#ifdef LINUX_STDIO
-		bp = (unsigned char *) --iob->_IO_read_ptr;
-		cnt = (long) iob->_IO_read_end - (long) iob->_IO_read_ptr;
-#elif defined(__DragonFly__)
-		bp = (unsigned char *) --((struct __FILE_public *)iob)->_p;
-		cnt = ++((struct __FILE_public *)iob)->_r;
-#else
-		bp = (unsigned char *) --iob->_ptr;
-		cnt = ++iob->_cnt;
-#endif
-		c = (cnt < i ? cnt : i);
+		/* Back up and store the current position and update cnt. */
+		bp = --m.readpos;
+		cnt = m.end - m.readpos;
+		c = (cnt < i) ? cnt : i;
 		if (ismbox && c > 1) {
 			/*
 			** packed maildrop - only take up to the (possible)
@@ -547,15 +538,8 @@ m_getfld(int state, unsigned char *name,
 			}
 		}
 		memcpy( buf, bp, c );
-#ifdef LINUX_STDIO
-		iob->_IO_read_ptr += c;
-#elif defined(__DragonFly__)
-		((struct __FILE_public *)iob)->_r -= c;
-		((struct __FILE_public *)iob)->_p += c;
-#else
-		iob->_cnt -= c;
-		iob->_ptr += c;
-#endif
+		/* Advance the current position to reflect the copy out. */
+		m.readpos += c;
 		if (bufsz < 0) {
 			msg_count = c;
 			return (state);
@@ -581,11 +565,13 @@ thisisanmbox(FILE *iob)
 	char *cp;
 	char *delimstr;
 
-	c = getc(iob); 
+	setup_buffer(iob, &m);
+
+	c = Getc(iob); 
 	if (feof(iob)) {
 		return;
 	}
-	ungetc(c, iob);
+	Ungetc(c, iob);
 
 	/*
 	** Figure out what the message delimitter string is for this
@@ -599,7 +585,12 @@ thisisanmbox(FILE *iob)
 	** abort.
 	*/
 
-	if (fread(text, sizeof(*text), 5, iob) != 5) {
+	for (c=0, cp=text; c<5; ++c, ++cp) {
+		if ((*cp = Getc(iob)) == EOF) {
+			break;
+		}
+	}
+	if (c != 5) {
 		adios(EX_IOERR, NULL, "Read error");
 	}
 	if (strncmp(text, "From ", 5)!=0) {
@@ -607,7 +598,7 @@ thisisanmbox(FILE *iob)
 	}
 	ismbox = TRUE;
 	delimstr = "\nFrom ";
-	while ((c = getc(iob)) != '\n' && c >= 0) {
+	while ((c = Getc(iob)) != '\n' && c >= 0) {
 		continue;
 	}
 	c = strlen(delimstr);
@@ -630,8 +621,9 @@ thisisanmbox(FILE *iob)
 	*/
 	pat_map = (unsigned char **) mh_xcalloc(256, sizeof(unsigned char *));
 
-	for (cp = (char *) fdelim + 1; cp < (char *) delimend; cp++ )
+	for (cp = (char *) fdelim + 1; cp < (char *) delimend; cp++) {
 		pat_map[(unsigned char)*cp] = (unsigned char *) cp;
+	}
 }
 
 
@@ -645,24 +637,31 @@ m_Eom(int c, FILE *iob)
 	long pos = 0L;
 	int i;
 	char text[10];
+	char *cp;
 
-	pos = ftell(iob);
-	if ((i = fread(text, sizeof *text, edelimlen, iob)) != edelimlen ||
-			(strncmp(text, (char *)edelim, edelimlen)!=0)) {
-		if (i == 0 && ismbox)
+	pos = m.readpos; /* ftell */
+	for (i=0, cp=text; i<edelimlen; ++i, ++cp) {
+		if ((*cp = Getc(iob)) == EOF) {
+			break;
+		}
+	}
+
+	if (i != edelimlen ||
+		(strncmp(text, (char *)edelim, edelimlen)!=0)) {
+		if (i == 0 && ismbox) {
 			/*
 			** the final newline in the (brain damaged) unix-format
 			** maildrop is part of the delimitter - delete it.
 			*/
 			return 1;
-
-		fseek(iob, (long)(pos-1), SEEK_SET);
-		getc(iob);  /* should be OK */
+		}
+		m.readpos = pos - 1;  /* fseek(iob, pos - 1, SEEK_SET) */
+		Getc(iob);  /* should be OK */
 		return 0;
 	}
 
 	if (ismbox) {
-		while ((c = getc(iob)) != '\n' && c >= 0) {
+		while ((c = Getc(iob)) != '\n' && c >= 0) {
 			continue;
 		}
 	}