…atting.

Integrates eyalroz/printf as a vendored dependency to replace all libc
snprintf/vsnprintf calls across the runtime. This gives us a consistent,
portable printf implementation across all platforms (including embedded
and bare-metal targets) with no platform-specific quirks.

Beyond the drop-in replacement, this extends the status formatting API
with streaming support:

- Add iree_status_format_to: callback-based streaming formatter that
  avoids contiguous buffers and pre-measurement passes. The callback
  returns bool for flow control, enabling early termination on buffer
  full or allocation failure.

- Add iree_string_builder_append_status: single-pass status-to-builder
  formatting via iree_status_format_to, resolving the status/string_builder
  dependency cycle that previously required a local copy in libhsa.c.

- Rewrite iree_status_fprint to stream directly to FILE* with zero
  heap allocation (previously required a contiguous buffer).

- Rewrite iree_status_to_string as single-pass using string builder
  instead of two-pass measure-then-format.

- Fix va_copy usage in status allocation: use C99 va_copy for the
  two-pass measure-then-format pattern instead of calling va_start
  twice on the same parameter (implementation-defined behavior).

- Convert Status::ToString (C++) and ApiStatusToString (Python bindings)
  from two-pass iree_status_format to single-pass iree_status_format_to.

- Replace HIP dynamic_symbols.c allocate-format-free pattern with
  direct iree_string_builder_append_status (eliminates intermediate
  heap allocation).

RISC-V toolchain fix: strip debug info from libgcc.a during CMake
configure. eyalroz/printf's long double support in %Lf/%Le compiles
va_arg(args, long double) which on RISC-V (128-bit quad precision)
generates references to __extenddftf2/__trunctfdf2 soft-float builtins.
These are resolved from libgcc.a, but the GCC 12.2.0-compiled objects
in that archive contain DWARF debug info with relocation types 60/61
(in .debug_rnglists and .debug_loclists sections) that LLD cannot
parse. The pre-built RISC-V toolchain lacks compiler-rt builtins as
an alternative, so we strip the debug metadata from libgcc.a at
configure time using llvm-objcopy --strip-debug. This preserves all
code and data sections and is idempotent. The strip runs inside the
RISCV_TOOLCHAIN_ROOT guard so users with their own toolchains are
unaffected. Verified locally with the same toolchain used in CI
(toolchain_iree_manylinux_2_28_20231012).

Co-Authored-By: Claude <[email protected]>