mtools: skip checks, add Darwin cross-compile workaround

package/mtools/patches/patch-config_c

@@ -0,0 +1,11 @@
+--- mtools-4.0.18.orig/config.c	2011-06-30 08:49:04.000000000 +0200
++++ mtools-4.0.18/config.c	2016-09-14 08:27:25.286075212 +0200
+@@ -54,7 +54,7 @@ static int token_nr; /* number of tokens
+ static char default_drive='\0'; /* default drive */
+ 
+ /* "environment" variables */
+-unsigned int mtools_skip_check=0;
++unsigned int mtools_skip_check=1;
+ unsigned int mtools_fat_compatibility=0;
+ unsigned int mtools_ignore_short_case=0;
+ unsigned int mtools_rate_0=0;

package/mtools/patches/patch-sysincludes_h

@@ -0,0 +1,11 @@
+--- mtools-4.0.18.orig/sysincludes.h	2013-01-07 23:45:56.000000000 +0100
++++ mtools-4.0.18/sysincludes.h	2016-09-14 08:46:14.000000000 +0200
+@@ -103,7 +103,7 @@ typedef void *caddr_t;
+ # define PACKED __attribute__ ((packed))
+ # if __GNUC__ == 2 && __GNUC_MINOR__ > 6 || __GNUC__ >= 3
+ /* gcc 2.6.3 doesn't have "unused" */		/* mool */
+-#  define UNUSED(x) x __attribute__ ((unused));x
++#  define UNUSED(x) x
+ #  define UNUSEDP __attribute__ ((unused))
+ # else
+ #  define UNUSED(x) x