avformat/img2dec: Attempt to detect non-escaped glob patterns too (-pattern_type glob)

Fixes ticket #3948

Based-on-patch-by: Michael Niedermayer <michaelni@gmx.at>
Signed-off-by: Alexander Strasser <eclipse7@gmx.net>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit e079d43af86c38a0c0efb9bc6058e1316e6a18f4)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
diff --git a/libavformat/img2dec.c b/libavformat/img2dec.c
index ee484f6..2969b51 100644
--- a/libavformat/img2dec.c
+++ b/libavformat/img2dec.c
@@ -162,6 +162,8 @@
             return AVPROBE_SCORE_MAX;
         else if (is_glob(p->filename))
             return AVPROBE_SCORE_MAX;
+        else if (p->filename[strcspn(p->filename, "*?{")]) // probably PT_GLOB
+            return AVPROBE_SCORE_EXTENSION + 2; // score chosen to be a tad above the image pipes
         else if (p->buf_size == 0)
             return 0;
         else if (av_match_ext(p->filename, "raw") || av_match_ext(p->filename, "gif"))