Disable stdcall fixup warnings (x86 only)

This warning is new in Binutils 2.42, and it regards fixing a long-time,
x86 bfd bug. Previously the fixup did not occur and bfd would fail to
locate decorated symbols. In the case of an entry point, bfd silently
linked the wrong address! It remains silent if the entry point is not
found, but the fixup makes it more likely to find the symbol.

The old, buggy behavior was an accident. It differs from MSVC and nobody
wants it. Theoretically some program might depend on the old behavior,
hence the warning, but it's incredibly unlikely, so silence the warning.

Author: skeeto

Dockerfile

@@ -67,6 +67,7 @@ ARG ARCH=x86_64-w64-mingw32
 WORKDIR /binutils-$BINUTILS_VERSION
 COPY src/binutils-*.patch $PREFIX/src/
 RUN sed -ri 's/(static bool insert_timestamp = )/\1!/' ld/emultempl/pe*.em \
+ && sed -ri 's/(int pe_enable_stdcall_fixup = )/\1!!/' ld/emultempl/pe*.em \
  && cat $PREFIX/src/binutils-*.patch | patch -p1
 WORKDIR /x-binutils
 RUN /binutils-$BINUTILS_VERSION/configure \