Specify default thread stack size for musl (#343)

The musl libc by default sets up threads to have [128kB of
stack](https://wiki.musl-libc.org/functional-differences-from-glibc.html).

We explicitly set our desired default stack size in the PT_GNU_STACK
header with this linker command. musl reads this header to determine the
default thread stack size. 2MB is approximately the glibc default.

Bench: 13566775

Author: 87flowers

CMakeLists.txt

@@ -66,6 +66,11 @@ function(target_add_flags target)
         -fsanitize=address,undefined
         >)
 
+    if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
+        target_link_options(${target} PUBLIC
+            -Wl,-z,stack-size=2097152)
+    endif()
+
     # Include directories
     target_include_directories(${target} PUBLIC src)