drcachesim failures on Mac: config path wrong and pipe ASSERT

The lib suffix is wrong:

# bin32/drrun -t drcachesim -- ~/derek/dr/test/hello
ERROR: tracer library ~/derek/dr/git/build_x86_dbg/bin32/../clients/lib32/debug/libdrmemtrace.so is unreadable

Pipe behavior is different in more ways than what's already been fixed:

# clients/bin32/drcachesim -dr_debug -dr <DR-path> -tracer clients/lib32/debug/libdrmemtrace.dylib -- ~/derek/dr/test/hello
<Starting application ~/derek/dr/test/hello (17814)>
<Initial options = -no_dynamic_options -client_lib 'clients/lib32/debug/libdrmemtrace.dylib;0;' -code_api -stack_size 56K -max_elide_jmp 0 -max_elide_call 0 -no_inline_ignored_syscalls -native_exec_default_list '' -no_native_exec_managed_code -no_indcall2direct >
<ran out of stolen fd space>
sizeof(long long)=8, x64 is 1311768467750060323
sizeof(_Bool) = 1, sizeof(meow) = 1
b=true, b2=false
Hello world!
Goodbye world!
x is 0x100000000
<app trying to close DR file(s)>
ASSERT FAILURE: ~/derek/dr/git/src/clients/drcachesim/tracer/tracer.cpp:145: false ()---- <application exited with code 65280> ----