Linux

add benchmark for stumpless_open_buffer_target #1175

Job	Run time
linux, debug	5m 38s
linux, debug, ansi	5m 12s
linux, release	6m 23s
linux, release, single file library	5m 45s
linux, release, static library	7m 39s
linux, all features disabled, debug	1m 45s
linux, all features disabled, release	3m 22s
linux, with c++, release	1m 26s
linux, with c++, debug	44s
linux, fuzzer build	20s
linux, release, ansi	6m 1s
	44m 15s

Provide feedback