Merge branch 'j6t/mingw'

* j6t/mingw: (38 commits)
  compat/pread.c: Add a forward declaration to fix a warning
  Windows: Fix ntohl() related warnings about printf formatting
  Windows: TMP and TEMP environment variables specify a temporary directory.
  Windows: Make 'git help -a' work.
  Windows: Work around an oddity when a pipe with no reader is written to.
  Windows: Make the pager work.
  When installing, be prepared that template_dir may be relative.
  Windows: Use a relative default template_dir and ETC_GITCONFIG
  Windows: Compute the fallback for exec_path from the program invocation.
  Turn builtin_exec_path into a function.
  Windows: Use a customized struct stat that also has the st_blocks member.
  Windows: Add a custom implementation for utime().
  Windows: Add a new lstat and fstat implementation based on Win32 API.
  Windows: Implement a custom spawnve().
  Windows: Implement wrappers for gethostbyname(), socket(), and connect().
  Windows: Work around incompatible sort and find.
  Windows: Implement asynchronous functions as threads.
  Windows: Disambiguate DOS style paths from SSH URLs.
  Windows: A rudimentary poll() emulation.
  Windows: Implement start_command().
  ...

help.c

@@ -391,6 +391,32 @@ static void pretty_print_string_list(struct cmdnames *cmds, int longest)
 	}
 }
 
+static int is_executable(const char *name)
+{
+	struct stat st;
+
+	if (stat(name, &st) || /* stat, not lstat */
+	    !S_ISREG(st.st_mode))
+		return 0;
+
+#ifdef __MINGW32__
+	/* cannot trust the executable bit, peek into the file instead */
+	char buf[3] = { 0 };
+	int n;
+	int fd = open(name, O_RDONLY);
+	st.st_mode &= ~S_IXUSR;
+	if (fd >= 0) {
+		n = read(fd, buf, 2);
+		if (n == 2)
+			/* DOS executables start with "MZ" */
+			if (!strcmp(buf, "#!") || !strcmp(buf, "MZ"))
+				st.st_mode |= S_IXUSR;
+		close(fd);
+	}
+#endif
+	return st.st_mode & S_IXUSR;
+}
+
 static unsigned int list_commands_in_dir(struct cmdnames *cmds,
 					 const char *path)
 {
@@ -404,15 +430,12 @@ static unsigned int list_commands_in_dir(struct cmdnames *cmds,
 		return 0;
 
 	while ((de = readdir(dir)) != NULL) {
-		struct stat st;
 		int entlen;
 
 		if (prefixcmp(de->d_name, prefix))
 			continue;
 
-		if (stat(de->d_name, &st) || /* stat, not lstat */
-		    !S_ISREG(st.st_mode) ||
-		    !(st.st_mode & S_IXUSR))
+		if (!is_executable(de->d_name))
 			continue;
 
 		entlen = strlen(de->d_name) - prefix_len;
@@ -447,7 +470,7 @@ static unsigned int load_command_list(void)
 
 	path = paths = xstrdup(env_path);
 	while (1) {
-		if ((colon = strchr(path, ':')))
+		if ((colon = strchr(path, PATH_SEP)))
 			*colon = 0;
 
 		len = list_commands_in_dir(&other_cmds, path);