Add architecture "x86_64"

Makefile.am

@@ -25,6 +25,10 @@ if ARCH_X86
 libkernaux_a_SOURCES += src/arch/x86.S
 endif
 
+if ARCH_X86_64
+libkernaux_a_SOURCES += src/arch/x86_64.S
+endif
+
 if ENABLE_CMDLINE
 libkernaux_a_SOURCES += src/cmdline.c
 TESTS += \

configure.ac

@@ -16,12 +16,14 @@ AC_ARG_ENABLE([multiboot2], AS_HELP_STRING([--disable-multiboot2], [disable Mult
 AC_ARG_ENABLE([pfa],        AS_HELP_STRING([--disable-pfa],        [disable Page Frame Allocator]))
 
 AM_CONDITIONAL([ARCH_X86],          [test "$host_cpu" = x86])
+AM_CONDITIONAL([ARCH_X86_64],       [test "$host_cpu" = x86_64])
 AM_CONDITIONAL([ENABLE_CMDLINE],    [test "$enable_cmdline"    != no])
 AM_CONDITIONAL([ENABLE_CONSOLE],    [test "$enable_console"    != no])
 AM_CONDITIONAL([ENABLE_MULTIBOOT2], [test "$enable_multiboot2" != no])
 AM_CONDITIONAL([ENABLE_PFA],        [test "$enable_pfa"        != no])
 
 AS_IF([test "$host_cpu" = x86],          [AC_DEFINE([ARCH_X86],          [1], [architecture is x86])])
+AS_IF([test "$host_cpu" = x86_64],       [AC_DEFINE([ARCH_X86_64],       [1], [architecture is x86_64])])
 AS_IF([test "$enable_cmdline"    != no], [AC_DEFINE([ENABLE_CMDLINE],    [1], [enabled command line parser])])
 AS_IF([test "$enable_console"    != no], [AC_DEFINE([ENABLE_CONSOLE],    [1], [enabled serial console])])
 AS_IF([test "$enable_multiboot2" != no], [AC_DEFINE([ENABLE_MULTIBOOT2], [1], [enabled Multiboot 2 information parser])])

include/Makefile.am

@@ -1,5 +1,6 @@
 nobase_include_HEADERS = \
 	kernaux/arch/x86.h \
+	kernaux/arch/x86_64.h \
 	kernaux/cmdline.h \
 	kernaux/console.h \
 	kernaux/multiboot2.h \

include/kernaux/arch/x86_64.h

@@ -0,0 +1,12 @@
+#ifndef KERNAUX_INCLUDED_ARCH_X86_64
+#define KERNAUX_INCLUDED_ARCH_X86_64 1
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

src/arch/x86_64.S

@@ -0,0 +1 @@
+#include "../config.h"