Change the linker's heuristic for computing the entry point for binaries so that shared libraries default to an entry point of 0.

	* ldlang.c (lang_end): When computing the entry point, only
	try the start address of the entry section when creating an
	executable.
	* ld.texi (Entry point): Update description of heuristic used to
	choose the entry point.
	testsuite/ld-alpha/tlspic.rd: Update expected entry point address.
	testsuite/ld-arm/tls-gdesc-got.d: Likewise.
	testsuite/ld-i386/tlsnopic.rd: Likewise.
	testsuite/ld-ia64/tlspic.rd: Likewise.
	testsuite/ld-sparc/gotop32.rd: Likewise.
	testsuite/ld-sparc/gotop64.rd: Likewise.
	testsuite/ld-sparc/tlssunnopic32.rd: Likewise.
	testsuite/ld-sparc/tlssunnopic64.rd: Likewise.
	testsuite/ld-sparc/tlssunpic32.rd: Likewise.
	testsuite/ld-sparc/tlssunpic64.rd: Likewise.
	testsuite/ld-tic6x/shlib-1.rd: Likewise.
	testsuite/ld-tic6x/shlib-1b.rd: Likewise.
	testsuite/ld-tic6x/shlib-1r.rd: Likewise.
	testsuite/ld-tic6x/shlib-1rb.rd: Likewise.
	testsuite/ld-tic6x/shlib-noindex.rd: Likewise.
	testsuite/ld-x86-64/pr14207.d: Likewise.
	testsuite/ld-x86-64/tlsdesc.rd: Likewise.
	testsuite/ld-x86-64/tlspic.rd: Likewise.
	testsuite/ld-x86-64/tlspic2.rd: Likewise.
22 files changed