Expand glob matching on POSIX

Previously, GlobMatchesPath would always use FNM_PATHNAME, which does
not let '*' match path separators.

Loosen this so GlobMatchesPath can be used to match "any path name
ending with 'xyz'" using "*xyz".

This is a change in behavior for POSIX systems, but it seems like the
Windows GlobMatchesPath always worked like this (being based on
PathMatchSpec), so it creates a unified behavior across platforms.

port.h

@@ -82,7 +82,7 @@ inline bool GlobMatchesPath(const char *glob, const char *path) {
 #include <fnmatch.h>
 
 inline bool GlobMatchesPath(const char *glob, const char *path) {
-  return fnmatch(glob, path, FNM_PATHNAME) == 0;
+  return fnmatch(glob, path, 0) == 0;
 }
 
 #endif  // #if defined(_WIN32)