rtlib: sys/io.h incorrectly included on systems that do not provide it

- fix rtlib compilation error on/for aarch64 (arm64) or other platforms
- use of sys/io.h is only to call ioperm(), and determine permission for direct use out in/out instructions
- sys/io.h is used only for x86, x86_64 and is unnecessary for all other linux targets (armhf ,arm64, mips ....)

Author: czsgaba

changelog.txt

@@ -48,6 +48,7 @@ Version 1.07.0
 - github #145: WSTRING concat and assign buffer (&=) overrun
 - sf.net #893: 'Suffixes are only valid in -lang' error message showing incorrect -lang options allowed
 - fbc uses '-march=armv8-a' instead of invalid option '-march=aarch64' when passing options to gcc/LLVM (czsgaba)
+- rtlib: sys/io.h incorrectly included on systems that do not provide it.  It is used only for x86, x86_64 and is unnecessary for all other linux targets (armhf ,arm64, mips ....)
 
 
 Version 1.06.0

src/rtlib/unix/hinit.c

@@ -8,9 +8,21 @@
 #include "../fb_private_thread.h"
 #include <signal.h>
 #include <termcap.h>
-#ifdef HOST_LINUX
-#include <sys/io.h>
+
+#if defined HOST_LINUX && (defined HOST_X86 || defined HOST_X86_64)
+	/*
+	The sys/ headers are architecture and OS dependent. They 
+	do not exist across all targets and io.h in particular 
+	is intended for very low-level non-portable uses often 
+	in coordination with the kernel. The only targets that 
+	provide sys/io.h are x86*, Alpha, IA64, and 32-bit ARM.
+	No other systems provide it.
+	From https://bugzilla.redhat.com/show_bug.cgi?id=1116162
+	or http://www.hep.by/gnu/gnulib/ioperm.html#ioperm
+	*/
+	#include <sys/io.h>
 #endif
+
 #include <sys/ioctl.h>
 #include <fcntl.h>