configure: common usage

supported switches:

-------------------

	--help

	--nickname

	--program-prefix

	--avoid-version

	--source-dir

	--pkgname

	--pkgdesc

	--pkgusrc

	--pkgrepo

	--pkgpsrc

	--pkgdurl

	--pkgdefs

	--pkglibs

	--prefix

	--exec-prefix

	--bindir

	--sbindir

	--libdir

	--includedir

	--oldincludedir

	--mandir

	--docdir

	--libexecdir

	--sysconfdir

	--sharedstatedir

	--localstatedir

	--runstatedir

	--datarootdir

	--datadir

	--infodir

	--localedir

	--htmldir

	--dvidir

	--pdfdir

	--psdir

	--build

	--host

	--cchost

	--cfghost

	--target

	--arch

	--compiler

	--toolchain

	--sysroot

	--cross-compile

	--shell

	--debug

	--strict

	--ccstrict

	--ldstrict

	--all-static

	--all-shared

	--enable-static

	--enable-shared

	--disable-static

	--disable-shared

	--enable-app

	--enable-frontend

	--disable-app

	--disable-frontend

	--enable-dependency-tracking

	--disable-dependency-tracking

supported variables:

--------------------

	NICKNAME

	SOURCE_DIR

	PREFIX

	EXEC_PREFIX

	BINDIR

	SBINDIR

	LIBDIR

	INCLUDEDIR

	MANDIR

	DOCDIR

	LIBEXECDIR

	SYSCONFDIR

	SHAREDSTATEDIR

	LOCALSTATEDIR

	RUNSTATEDIR

	DATAROOTDIR

	DATADIR

	INFODIR

	LOCALEDIR

	HTMLDIR

	DVIDIR

	PDFDIR

	PSDIR

	CC

	CPP

	CXX

	BUILD

	HOST

	CCHOST

	CFGHOST

	TARGET

	ARCH

	COMPILER

	TOOLCHAIN

	SYSROOT

	CROSS_COMPILE

	SHELL

	CFLAGS

	CFLAGS_DEBUG

	CFLAGS_COMMON

	CFLAGS_CMDLINE

	CFLAGS_CONFIG

	CFLAGS_SYSROOT

	CFLAGS_OS

	CFLAGS_SITE

	CFLAGS_PATH

	CFLAGS_STRICT

	CFLAGS_UTIL

	CFLAGS_LAST

	CFLAGS_ONCE

	LDFLAGS

	LDFLAGS_DEBUG

	LDFLAGS_COMMON

	LDFLAGS_CMDLINE

	LDFLAGS_CONFIG

	LDFLAGS_SYSROOT

	LDFLAGS_PATH

	LDFLAGS_STRICT

	LDFLAGS_UTIL

	LDFLAGS_LAST

	LDFLAGS_ONCE

	PE_SUBSYSTEM

	PE_IMAGE_BASE

	PE_CONFIG_DEFS

	ELF_EH_FRAME

	ELF_HASH_STYLE

	ELF_CONFIG_DEFS

	NATIVE_CC

	NATIVE_CPP

	NATIVE_CXX

	NATIVE_HOST

	NATIVE_CFGHOST

	NATIVE_CFLAGS

	NATIVE_LDFLAGS

	NATIVE_OS

	NATIVE_OS_BITS

	NATIVE_OS_UNDERSCORE