compat: Add implementation of getline from gnulib.

These were copied from the gnulib git repository as of:

	commit 563c779682040ed4b89c9b4bbe428dcd8157c90a

They come under the GNU GPL v3 (or later) exactly as notmuch is
licensed.

compat/getdelim.c

@@ -0,0 +1,133 @@
+/* getdelim.c --- Implementation of replacement getdelim function.
+   Copyright (C) 1994, 1996, 1997, 1998, 2001, 2003, 2005, 2006, 2007,
+   2008, 2009 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 3, or (at
+   your option) any later version.
+
+   This program is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+   02110-1301, USA.  */
+
+/* Ported from glibc by Simon Josefsson. */
+
+#include <config.h>
+
+#include <stdio.h>
+
+#include <limits.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <errno.h>
+
+#ifndef SSIZE_MAX
+# define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
+#endif
+
+#if USE_UNLOCKED_IO
+# include "unlocked-io.h"
+# define getc_maybe_unlocked(fp)	getc(fp)
+#elif !HAVE_FLOCKFILE || !HAVE_FUNLOCKFILE || !HAVE_DECL_GETC_UNLOCKED
+# undef flockfile
+# undef funlockfile
+# define flockfile(x) ((void) 0)
+# define funlockfile(x) ((void) 0)
+# define getc_maybe_unlocked(fp)	getc(fp)
+#else
+# define getc_maybe_unlocked(fp)	getc_unlocked(fp)
+#endif
+
+/* Read up to (and including) a DELIMITER from FP into *LINEPTR (and
+   NUL-terminate it).  *LINEPTR is a pointer returned from malloc (or
+   NULL), pointing to *N characters of space.  It is realloc'ed as
+   necessary.  Returns the number of characters read (not including
+   the null terminator), or -1 on error or EOF.  */
+
+ssize_t
+getdelim (char **lineptr, size_t *n, int delimiter, FILE *fp)
+{
+  ssize_t result;
+  size_t cur_len = 0;
+
+  if (lineptr == NULL || n == NULL || fp == NULL)
+    {
+      errno = EINVAL;
+      return -1;
+    }
+
+  flockfile (fp);
+
+  if (*lineptr == NULL || *n == 0)
+    {
+      char *new_lineptr;
+      *n = 120;
+      new_lineptr = (char *) realloc (*lineptr, *n);
+      if (new_lineptr == NULL)
+	{
+	  result = -1;
+	  goto unlock_return;
+	}
+      *lineptr = new_lineptr;
+    }
+
+  for (;;)
+    {
+      int i;
+
+      i = getc_maybe_unlocked (fp);
+      if (i == EOF)
+	{
+	  result = -1;
+	  break;
+	}
+
+      /* Make enough space for len+1 (for final NUL) bytes.  */
+      if (cur_len + 1 >= *n)
+	{
+	  size_t needed_max =
+	    SSIZE_MAX < SIZE_MAX ? (size_t) SSIZE_MAX + 1 : SIZE_MAX;
+	  size_t needed = 2 * *n + 1;   /* Be generous. */
+	  char *new_lineptr;
+
+	  if (needed_max < needed)
+	    needed = needed_max;
+	  if (cur_len + 1 >= needed)
+	    {
+	      result = -1;
+	      errno = EOVERFLOW;
+	      goto unlock_return;
+	    }
+
+	  new_lineptr = (char *) realloc (*lineptr, needed);
+	  if (new_lineptr == NULL)
+	    {
+	      result = -1;
+	      goto unlock_return;
+	    }
+
+	  *lineptr = new_lineptr;
+	  *n = needed;
+	}
+
+      (*lineptr)[cur_len] = i;
+      cur_len++;
+
+      if (i == delimiter)
+	break;
+    }
+  (*lineptr)[cur_len] = '\0';
+  result = cur_len ? cur_len : result;
+
+ unlock_return:
+  funlockfile (fp); /* doesn't set errno */
+
+  return result;
+}

compat/getline.c

@@ -0,0 +1,29 @@
+/* getline.c --- Implementation of replacement getline function.
+   Copyright (C) 2005, 2006, 2007 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 3, or (at
+   your option) any later version.
+
+   This program is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+   02110-1301, USA.  */
+
+/* Written by Simon Josefsson. */
+
+#include <config.h>
+
+#include <stdio.h>
+
+ssize_t
+getline (char **lineptr, size_t *n, FILE *stream)
+{
+  return getdelim (lineptr, n, '\n', stream);
+}