add option to disable setsid #124

Job	Run time
dpdk gcc	1m 51s
linux deb no dpdk	4m 33s
osx clang --disable-ssl	51s
linux gcc --disable-ssl	1m 1s
linux clang --disable-ssl	1m 21s
linux gcc c99	1m 37s
linux clang c99	1m 40s
linux gcc test	2m 0s
linux clang test asan	2m 24s
linux clang test ubsan	2m 21s
linux gcc test --enable-shared	1m 38s
linux clang test --enable-shared	2m 50s
linux gcc test dpdk	2m 21s
linux clang test dpdk	2m 48s
linux gcc test -ljemalloc	1m 30s
linux clang test -ljemalloc	1m 35s
linux gcc --enable-afxdp	1m 24s
linux clang --enable-afxdp	1m 7s
linux gcc dpdk --enable-shared	2m 8s
linux clang dpdk --enable-shared	1m 21s
linux gcc dpdk-shared	1m 39s
linux clang dpdk-shared	1m 11s
linux gcc dpdk-shared --enable-shared	2m 14s
linux clang dpdk-shared --enable-shared	1m 27s
linux gcc m32 --disable-ssl	1m 52s
	46m 44s

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