gdbserver not interruptible with Ctrl+C when waiting for connections

[Karl-Philipp Richter]

Running `gdbserver localhost:2345 /bin/echo abc` causes `gdbserver` to block at `Listening on port 2345` and isn't interruptible with Ctrl+C, but needs to be killed with `SIGINT` externally.

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: gdbserver 7.10-1ubuntu2
Uname: Linux 4.3.0-040300-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia
ApportVersion: 2.19.1-0ubuntu5
Architecture: amd64
Date: Sun Dec 6 06:58:29 2015
Dependencies:
 gcc-5-base 5.2.1-23ubuntu1~15.10 [origin: LP-PPA-ubuntu-toolchain-r-test]
 libc6 2.21-0ubuntu4
 libgcc1 1:5.2.1-23ubuntu1~15.10 [origin: LP-PPA-ubuntu-toolchain-r-test]
InstallationDate: Installed on 2015-09-14 (82 days ago)
InstallationMedia: Ubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422)
MarkForUpload: True
SourcePackage: gdb
SystemImageInfo: Error: command ['system-image-cli', '-i'] failed with exit code 2:
UpgradeStatus: Upgraded to wily on 2015-10-23 (43 days ago)