build system: drop PLATFORM_LINUX

PLATFORM_LINUX is a hidden configuration option which is disabled by
default and enabled at over a hundred locations for features that are
deemed to be Linux specific.

The only effect of PLATFORM_LINUX is to control compilation of
libbb/match_fstype.c.  This file is only needed by mount and umount.

Remove all references to PLATFORM_LINUX and compile match_fstype.c
if mount or umount is enabled.

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

console-tools/chvt.c

@@ -9,7 +9,6 @@
 //config:config CHVT
 //config:	bool "chvt (2 kb)"
 //config:	default y
-//config:	select PLATFORM_LINUX
 //config:	help
 //config:	This program is used to change to another terminal.
 //config:	Example: chvt 4 (change to terminal /dev/tty4)

console-tools/deallocvt.c

@@ -10,7 +10,6 @@
 //config:config DEALLOCVT
 //config:	bool "deallocvt (1.9 kb)"
 //config:	default y
-//config:	select PLATFORM_LINUX
 //config:	help
 //config:	This program deallocates unused virtual consoles.
 

console-tools/dumpkmap.c

@@ -9,7 +9,6 @@
 //config:config DUMPKMAP
 //config:	bool "dumpkmap (1.6 kb)"
 //config:	default y
-//config:	select PLATFORM_LINUX
 //config:	help
 //config:	This program dumps the kernel's keyboard translation table to
 //config:	stdout, in binary format. You can then use loadkmap to load it.

console-tools/fgconsole.c

@@ -9,7 +9,6 @@
 //config:config FGCONSOLE
 //config:	bool "fgconsole (1.5 kb)"
 //config:	default y
-//config:	select PLATFORM_LINUX
 //config:	help
 //config:	This program prints active (foreground) console number.
 

console-tools/kbd_mode.c

@@ -11,7 +11,6 @@
 //config:config KBD_MODE
 //config:	bool "kbd_mode (4.1 kb)"
 //config:	default y
-//config:	select PLATFORM_LINUX
 //config:	help
 //config:	This program reports and sets keyboard mode.
 

console-tools/loadfont.c

@@ -12,14 +12,12 @@
 //config:config LOADFONT
 //config:	bool "loadfont (5.2 kb)"
 //config:	default y
-//config:	select PLATFORM_LINUX
 //config:	help
 //config:	This program loads a console font from standard input.
 //config:
 //config:config SETFONT
 //config:	bool "setfont (24 kb)"
 //config:	default y
-//config:	select PLATFORM_LINUX
 //config:	help
 //config:	Allows to load console screen map. Useful for i18n.
 //config:

console-tools/loadkmap.c

@@ -9,7 +9,6 @@
 //config:config LOADKMAP
 //config:	bool "loadkmap (1.8 kb)"
 //config:	default y
-//config:	select PLATFORM_LINUX
 //config:	help
 //config:	This program loads a keyboard translation table from
 //config:	standard input.

console-tools/openvt.c

@@ -10,7 +10,6 @@
 //config:config OPENVT
 //config:	bool "openvt (7.2 kb)"
 //config:	default y
-//config:	select PLATFORM_LINUX
 //config:	help
 //config:	This program is used to start a command on an unused
 //config:	virtual terminal.

console-tools/setconsole.c

@@ -10,7 +10,6 @@
 //config:config SETCONSOLE
 //config:	bool "setconsole (3.6 kb)"
 //config:	default y
-//config:	select PLATFORM_LINUX
 //config:	help
 //config:	Redirect writes to /dev/console to another device,
 //config:	like the current tty while logged in via telnet.

console-tools/setkeycodes.c

@@ -11,7 +11,6 @@
 //config:config SETKEYCODES
 //config:	bool "setkeycodes (2.1 kb)"
 //config:	default y
-//config:	select PLATFORM_LINUX
 //config:	help
 //config:	This program loads entries into the kernel's scancode-to-keycode
 //config:	map, allowing unusual keyboards to generate usable keycodes.

console-tools/setlogcons.c

@@ -11,7 +11,6 @@
 //config:config SETLOGCONS
 //config:	bool "setlogcons (1.8 kb)"
 //config:	default y
-//config:	select PLATFORM_LINUX
 //config:	help
 //config:	This program redirects the output console of kernel messages.
 

console-tools/showkey.c

@@ -9,7 +9,6 @@
 //config:config SHOWKEY
 //config:	bool "showkey (4.7 kb)"
 //config:	default y
-//config:	select PLATFORM_LINUX
 //config:	help
 //config:	Shows keys pressed.