More portable handling of loop header files, as done in util-linux

libbb/mk_loop_h.sh

@@ -0,0 +1,34 @@
+#!/bin/sh
+#
+# Figure out (i) the type of dev_t (ii) the defines for loop stuff
+#
+
+rm -f loop.h
+
+# Since 1.3.79 there is an include file <asm/posix_types.h>
+# that defines __kernel_dev_t.
+# (The file itself appeared in 1.3.78, but there it defined __dev_t.)
+# If it exists, we use it, or, rather, <linux/posix_types.h> which
+# avoids namespace pollution.  Otherwise we guess that __kernel_dev_t
+# is an unsigned short (which is true on i386, but false on alpha).
+
+if [ -f /usr/include/linux/posix_types.h ]; then
+   echo '#include <linux/posix_types.h>' >> loop.h
+   echo '#undef dev_t' >> loop.h
+   echo '#define dev_t __kernel_dev_t' >> loop.h
+else
+   echo '#undef dev_t' >> loop.h
+   echo '#define dev_t unsigned short' >> loop.h
+fi
+
+# Next we have to find the loop stuff itself.
+# First try kernel source, then a private version.
+
+if [ -f /usr/include/linux/loop.h ]; then
+   echo '#include <linux/loop.h>' >> loop.h
+else
+   echo '#include "real_loop.h"' >> loop.h
+fi
+
+echo '#undef dev_t' >> loop.h
+