Update libmagic patch

This simplifies the libmagic patch:
- in upstream the HAVE_STRERROR check has been removed
- in upstream library the HAVE_SIGNAL_H has been removed
- indentations syncs with the upstream library
- some irrelevant changes removed from the patch (log comment), upstream
  has this correctly logged already so no need to patch the comment.

Closes GH-4298

Author: petk

ext/fileinfo/generate_patch.sh

@@ -1,4 +1,4 @@
-VERSION=5.33
+VERSION=5.37
 if [[ ! -d libmagic.orig ]]; then
   mkdir libmagic.orig
   wget -O - ftp://ftp.astron.com/pub/file/file-$VERSION.tar.gz \