Add 2 testcases for PR ld/22269

Since undefined weak symbols in static PIE are always resolved to 0 at
run-time, linker should resolve them as 0 at link-time, regardless of
whether "-z dynamic-undefined-weak" is used.  "-z dynamic-undefined-weak"
only makes undefined weak symbols dynamic, but doesn't change undefined
weak symbol resolution in static PIE at link-time.  These tests currently
pass on x86, but fails on many other targets.

The framework to resolve weak symbols in static PE at link-time is
posted at

https://sourceware.org/ml/binutils/2017-10/msg00087.html

which requires users/hjl/check_relocs branch to call check_relocs after
opening all inputs.  I will submit backend patches for failling targets
after merging users/hjl/check_relocs branch next.

	* PR ld/22269
	* testsuite/ld-elf/pr22269.s: New file.
	* testsuite/ld-elf/pr22269a.d: Likewise.
	* testsuite/ld-elf/pr22269b.d: Likewise.

ld/ChangeLog

@@ -1,3 +1,10 @@
+2017-10-11  H.J. Lu  <hongjiu.lu@intel.com>
+
+	* PR ld/22269
+	* testsuite/ld-elf/pr22269.s: New file.
+	* testsuite/ld-elf/pr22269a.d: Likewise.
+	* testsuite/ld-elf/pr22269b.d: Likewise.
+
 2017-10-11  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* testsuite/ld-i386/i386.exp: Run pr19636-1j, pr19636-1k,

ld/testsuite/ld-elf/pr22269.s

@@ -0,0 +1,13 @@
+	.globl main
+	.globl start
+	.globl _start
+	.globl __start
+	.text
+main:
+start:
+_start:
+__start:
+	.byte 0
+	.section	.data.rel.ro.local,"aw",%progbits
+	.weak func
+	.dc.a func

ld/testsuite/ld-elf/pr22269a.d

@@ -0,0 +1,10 @@
+#name: PR ld/22269
+#source: pr22269.s
+#ld: -pie --no-dynamic-linker
+#readelf: -r -x .data.rel.ro
+#target: *-*-linux* *-*-gnu* *-*-nacl*
+
+There are no relocations in this file.
+
+Hex dump of section '.data.rel.ro':
+  0x[a-f0-9]+ [0 ]+[ ]+.+

ld/testsuite/ld-elf/pr22269b.d

@@ -0,0 +1,10 @@
+#name: PR ld/22269 (-z dynamic-undefined-weak)
+#source: pr22269.s
+#ld: -pie --no-dynamic-linker -z dynamic-undefined-weak
+#readelf: -r -x .data.rel.ro
+#target: *-*-linux* *-*-gnu* *-*-nacl*
+
+There are no relocations in this file.
+
+Hex dump of section '.data.rel.ro':
+  0x[a-f0-9]+ [0 ]+[ ]+.+