Merge branch 'sp/mmap'

* sp/mmap: (27 commits)
  Spell default packedgitlimit slightly differently
  Increase packedGit{Limit,WindowSize} on 64 bit systems.
  Update packedGit config option documentation.
  mmap: set FD_CLOEXEC for file descriptors we keep open for mmap()
  pack-objects: fix use of use_pack().
  Fix random segfaults in pack-objects.
  Cleanup read_cache_from error handling.
  Replace mmap with xmmap, better handling MAP_FAILED.
  Release pack windows before reporting out of memory.
  Default core.packdGitWindowSize to 1 MiB if NO_MMAP.
  Test suite for sliding window mmap implementation.
  Create pack_report() as a debugging aid.
  Support unmapping windows on 'temporary' packfiles.
  Improve error message when packfile mmap fails.
  Ensure core.packedGitWindowSize cannot be less than 2 pages.
  Load core configuration in git-verify-pack.
  Fully activate the sliding window pack access.
  Unmap individual windows rather than entire files.
  Document why header parsing won't exceed a window.
  Loop over pack_windows when inflating/accessing data.
  ...

Conflicts:

	cache.h
	pack-check.c

write_or_die.c

@@ -1,5 +1,21 @@
 #include "cache.h"
 
+void read_or_die(int fd, void *buf, size_t count)
+{
+	char *p = buf;
+	ssize_t loaded;
+
+	while (count > 0) {
+		loaded = xread(fd, p, count);
+		if (loaded == 0)
+			die("unexpected end of file");
+		else if (loaded < 0)
+			die("read error (%s)", strerror(errno));
+		count -= loaded;
+		p += loaded;
+	}
+}
+
 void write_or_die(int fd, const void *buf, size_t count)
 {
 	const char *p = buf;