Hi,
This patch is to calculate correct address of 'next pc' of syscall
sigreturn and rt_sigreturn.

Tested on armv7l-unknown-linux-gnueabi, and a diff of test summary is
shown below:

-FAIL: gdb.base/sigstep.exp: step from handler; leave handler(timeout)
+PASS: gdb.base/sigstep.exp: step from handler; leave handler
-FAIL: gdb.base/sigstep.exp: stepi from handleri; leave signal trampoline
+PASS: gdb.base/sigstep.exp: stepi from handleri; leave signal trampoline (in main)
-FAIL: gdb.base/sigstep.exp: next from handler; leave handler (timeout)
+PASS: gdb.base/sigstep.exp: next from handler; leave handler
-FAIL: gdb.base/sigstep.exp: nexti from handleri; leave signal trampoline
+PASS: gdb.base/sigstep.exp: nexti from handleri; leave signal trampoline (in main)

                === gdb Summary ===

-# of expected passes           14664
-# of unexpected failures       314
+# of expected passes           14669
+# of unexpected failures       310

Is that OK?

-- 
Yao Qi
CodeSourcery
yao@codesourcery.com
(650) 331-3385 x739