# Patches

This version ships two small patches on top of upstream GNU m4 1.4.20:

- **`windows-binary-mode.patch`** — At the start of `output_init()` in `src/output.c`, call `SET_BINARY(STDOUT_FILENO)`
when `SET_BINARY` is defined. On Windows, the C runtime defaults text mode on stdout, which translates newlines to
CRLF. m4 must write its output in binary mode so generated files are not corrupted; this matches the usual MinGW/MSVC
pattern for binary-safe stdout.

- **`stdint-comment-subst.patch`** — In `lib/stdint.in.h`, the comment that mentions the autoconf token `@NEXT_STDINT_H@`
is rewritten so the `@...@` sequence is split with spaces (`@ NEXT_STDINT_H @`). That keeps the comment readable but avoids
accidental processing of the token as a substitution placeholder by tooling that scans for `@NAME@` patterns during the
Bazel build.

- **`musl-libc-compat.patch`** - Replaces #error directives in gnulib's `fpending.c` and `freadahead.c` with safe `return 1`
fallbacks, allowing M4 to compile on platforms with opaque `FILE` structs (e.g. musl libc) where these files would otherwise
fail to build. This mirrors the approach taken by rules_m4 (see [jmillikin/rules_m4#275873f27e9aa74fcf6ea22a381cc63fbd487888](https://github.com/jmillikin/rules_m4/commit/275873f27e9aa74fcf6ea22a381cc63fbd487888)),
which stubs out these functions because musl provides `**fpending` and `**freadahead` natively and these gnulib replacements
should not be compiled in the first place.