* configure: Make enable_threads and enable_shared defaults
	explicit.  Substitute enable_threads into generated Makefiles.
	* configure.in: Accept *-*-linux* not just *-*-linux-gnu*.
	* libtool.m4: Accept *-*-linux* not just *-*-linux-gnu*.
gcc:
	* configure.in: Accept *-*-linux* not just *-*-linux-gnu*.
	* fixinc/inclhack.def: Likewise.
	* fixinc/mkfixinc.sh: Likewise.
	* configure: Regenerate.
	* fixinc/fixincl.x: Regenerate.
	* install.texi: Document equivalence of linux and linux-gnu.
libio:
	* configure.in: Accept *-*-linux* not just *-*-linux-gnu*.
	Honor --disable-threads.
libstdc++:
	* configure.in: Accept *-*-linux* not just *-*-linux-gnu*.
	Honor --disable-threads.
libstdc++-v3:
	* configure: Regenerate after change to ../libtool.m4.
libobjc:
	* configure: Regenerate after change to ../libtool.m4.

From-SVN: r35680