Fix compilation on case insensitive filesystems

In such filesystems, including either Magic.h or magic.h does not
make any difference and the one or other file is included depending
on the search order. In this case, Magic.h was trying to include
itself instead of including magic.h.

src/Format.cpp

@@ -23,7 +23,7 @@
 #include "support/filetools.h"
 #include "support/gettext.h"
 #include "support/lstrings.h"
-#include "support/Magic.h"
+#include "support/lyxmagic.h"
 #include "support/mutex.h"
 #include "support/os.h"
 #include "support/PathChanger.h"

src/support/Makefile.am

@@ -74,9 +74,9 @@ liblyxsupport_a_SOURCES = \
 	lstrings.h \
 	lyxalgo.h \
 	lyxlib.h \
+	lyxmagic.h \
 	lyxtime.cpp \
 	lyxtime.h \
-	Magic.h \
 	mutex.h \
 	mutex.cpp \
 	Messages.cpp \

src/support/lyxmagic.h

@@ -1,6 +1,6 @@
 // -*- C++ -*-
 /**
- * \file Magic.h
+ * \file lyxmagic.h
  * This file is part of LyX, the document processor.
  * Licence details can be found in the file COPYING.
  *