PR gdb/22046: Fix T-stopped detach regression on old Linux kernels
    
    On <=RHEL6 hosts Fedora/RHEL GDB started to 'kill -STOP' all processes it
    detached.  Even those not originally T-stopped.  This is a Fedora-specific
    patch which is based on upstream GDB's PROC_STATE_STOPPED state.
    
    I believe (I did not verify) this patch did regress it:
    commit d617208bb06bd461b52ce041d89f7127e3044762
    Author: Pedro Alves <palves@redhat.com>
    Date:   Mon Jul 25 12:42:17 2016 +0100
        linux-procfs: Introduce enum proc_state
    
    As originally there was strstr() but now there is strcmp() and so the missing
    trailing '\n' no longer matches.
    
    The Bug was found by Michal Kolar.
    
    Reproducibility:
    $ gdb -p $PID
    (gdb) quit
    $ ...
    
    Actual results:
    ===
    RHEL6.9 x86_64 # scl enable devtoolset-7 bash
    RHEL6.9 x86_64 # which gdb
    /opt/rh/devtoolset-7/root/usr/bin/gdb
    RHEL6.9 x86_64 # ./testcase.sh
    24737 pts/0    S+     0:00 /bin/sleep 4
    24737 pts/0    T+     0:00 /bin/sleep 4
    RHEL6.9 x86_64 #
    ===
    
    Expected results:
    ===
    RHEL6.9 x86_64 # which gdb
    /usr/bin/gdb
    RHEL6.9 x86_64 # ./testcase.sh
    24708 pts/0    S+     0:00 /bin/sleep 4
    24708 pts/0    S+     0:00 /bin/sleep 4
    ./testcase.sh: line 20: kill: (24708) - No such process
    RHEL6.9 x86_64 #
    ===
    
    gdb/ChangeLog
    2017-09-01  Jan Kratochvil  <jan.kratochvil@redhat.com>
    
    	PR gdb/22046
    	* nat/linux-procfs.c (parse_proc_status_state): Fix PROC_STATE_STOPPED
    	detection.