From bf2780ced75501e9f3d4120d37f7cf0718e101f9 Mon Sep 17 00:00:00 2001
From: Peter0x44 <peter0x44@disroot.org>
Date: Sun, 9 Aug 2026 16:05:29 -0500
Subject: [PATCH 1/2] Add x86 multilib toolchain support

Keep x86_64 as the default output while enabling the GCC and mingw-w64
32-bit multilib under lib32. Build 32-bit support archives, CRT
libraries, and winpthreads for both the bootstrap and final sysroots so
each compiler stage has a complete i686 runtime.

Use pentium4 as the 32-bit architecture baseline. Add a GCC specs rule
that defaults _WIN32_WINNT to 0x0501 only under -m32 and only when the
caller has not supplied a value, preserving the existing x64 default and
explicit overrides.

Retain the x86_64-w64-mingw32-prefixed tools and add a separate build
step for an i686-w64-mingw32 interface. Compiler drivers inject -m32.
Target-sensitive binutils select their 32-bit modes explicitly: as uses
--32, ld uses -m i386pe, dlltool uses -m i386 with --as-flags=--32, and
windres uses --target=pe-i386. Input-driven inspection and archive tools
forward without a target override.

These forwarding executables provide both prefixed interfaces without
duplicating a second binutils installation. They deliberately remain
selectors for the underlying x86_64-configured multilib compiler rather
than spoofing its configured target identity.

Direct, Autoconf, CMake, and Libtool probes using the i686-prefixed
interface all produced PE-i386 output.
---
 Dockerfile | 98 +++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 89 insertions(+), 9 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index 391f9b4..c7d1181 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -272,6 +272,8 @@ RUN cat $PREFIX/src/gcc-*.patch | patch -d/dl/gcc -p1 \
  && /dl/gcc/configure \
         --prefix=/bootstrap \
         --with-sysroot=/bootstrap \
+        --with-arch-32=pentium4 \
+        "--with-specs=%{m32:%{!D_WIN32_WINNT*:-D_WIN32_WINNT=0x0501}}" \
         --target=$ARCH \
         --enable-static \
         --disable-shared \
@@ -285,7 +287,6 @@ RUN cat $PREFIX/src/gcc-*.patch | patch -d/dl/gcc -p1 \
         --disable-dependency-tracking \
         --disable-nls \
         --disable-lto \
-        --disable-multilib \
         CFLAGS_FOR_TARGET="-O2" \
         CXXFLAGS_FOR_TARGET="-O2" \
         LDFLAGS_FOR_TARGET="-s" \
@@ -298,13 +299,19 @@ RUN cat $PREFIX/src/gcc-*.patch | patch -d/dl/gcc -p1 \
 ENV PATH="/bootstrap/bin:${PATH}"
 
 COPY src/libmemory.c src/libchkstk.S $PREFIX/src/
-RUN mkdir -p $PREFIX/lib \
+RUN mkdir -p $PREFIX/lib $PREFIX/lib32 /bootstrap/lib32 \
  && CC=$ARCH-gcc AR=$ARCH-ar DESTDIR=$PREFIX/lib/ \
         sh $PREFIX/src/libmemory.c \
  && ln $PREFIX/lib/libmemory.a /bootstrap/lib/ \
  && CC=$ARCH-gcc AR=$ARCH-ar DESTDIR=$PREFIX/lib/ \
         sh $PREFIX/src/libchkstk.S \
- && ln $PREFIX/lib/libchkstk.a /bootstrap/lib/
+ && ln $PREFIX/lib/libchkstk.a /bootstrap/lib/ \
+ && CC="$ARCH-gcc -m32" AR=$ARCH-ar DESTDIR=$PREFIX/lib32/ \
+        sh $PREFIX/src/libmemory.c \
+ && ln $PREFIX/lib32/libmemory.a /bootstrap/lib32/ \
+ && CC="$ARCH-gcc -m32" AR=$ARCH-ar DESTDIR=$PREFIX/lib32/ \
+        sh $PREFIX/src/libchkstk.S \
+ && ln $PREFIX/lib32/libchkstk.a /bootstrap/lib32/
 
 WORKDIR /x-mingw-crt
 RUN /dl/mingw/mingw-w64-crt/configure \
@@ -313,7 +320,7 @@ RUN /dl/mingw/mingw-w64-crt/configure \
         --host=$ARCH \
         --with-default-msvcrt=msvcrt-os \
         --disable-dependency-tracking \
-        --disable-lib32 \
+        --enable-lib32 \
         --enable-lib64 \
         CFLAGS="-O2" \
         LDFLAGS="-s" \
@@ -332,6 +339,20 @@ RUN /dl/mingw/mingw-w64-libraries/winpthreads/configure \
  && make -j$(nproc) \
  && make install
 
+WORKDIR /x-winpthreads32
+RUN /dl/mingw/mingw-w64-libraries/winpthreads/configure \
+       --prefix=/bootstrap \
+       --libdir=/bootstrap/lib32 \
+       --with-sysroot=/bootstrap \
+       --host=$ARCH \
+       --enable-static \
+       --disable-shared \
+       CC="$ARCH-gcc -m32" \
+       CFLAGS="-O2" \
+       LDFLAGS="-s" \
+ && make -j$(nproc) \
+ && make install
+
 WORKDIR /x-gcc
 RUN make -j$(nproc) \
  && make install
@@ -417,7 +438,7 @@ RUN /dl/mingw/mingw-w64-crt/configure \
         --host=$ARCH \
         --with-default-msvcrt=msvcrt-os \
         --disable-dependency-tracking \
-        --disable-lib32 \
+        --enable-lib32 \
         --enable-lib64 \
         CFLAGS="-O2" \
         LDFLAGS="-s" \
@@ -428,7 +449,11 @@ COPY src/threads.c $PREFIX/src/
 COPY src/threads.h $PREFIX/include/
 RUN $ARCH-gcc -c -Oz -I$PREFIX/include/ \
         -ffunction-sections -Wa,--no-pad-sections $PREFIX/src/threads.c \
- && $ARCH-ar r $PREFIX/lib/libmingwex.a threads.o
+ && $ARCH-ar r $PREFIX/lib/libmingwex.a threads.o \
+ && $ARCH-gcc -m32 -c -Oz -I$PREFIX/include/ \
+        -ffunction-sections -Wa,--no-pad-sections \
+        -o threads32.o $PREFIX/src/threads.c \
+ && $ARCH-ar r $PREFIX/lib32/libmingwex.a threads32.o
 
 WORKDIR /winpthreads
 RUN /dl/mingw/mingw-w64-libraries/winpthreads/configure \
@@ -442,6 +467,20 @@ RUN /dl/mingw/mingw-w64-libraries/winpthreads/configure \
  && make -j$(nproc) \
  && make install
 
+WORKDIR /winpthreads32
+RUN /dl/mingw/mingw-w64-libraries/winpthreads/configure \
+       --prefix=$PREFIX \
+       --libdir=$PREFIX/lib32 \
+       --with-sysroot=$PREFIX \
+       --host=$ARCH \
+       --enable-static \
+       --disable-shared \
+       CC="$ARCH-gcc -m32" \
+       CFLAGS="-O2" \
+       LDFLAGS="-s" \
+ && make -j$(nproc) \
+ && make install
+
 WORKDIR /gcc
 COPY src/crossgcc-*.patch $PREFIX/src/
 RUN cat $PREFIX/src/crossgcc-*.patch | patch -d/dl/gcc -p1 \
@@ -449,6 +488,8 @@ RUN cat $PREFIX/src/crossgcc-*.patch | patch -d/dl/gcc -p1 \
         --prefix=$PREFIX \
         --with-sysroot=$PREFIX \
         --with-native-system-header-dir=/include \
+        --with-arch-32=pentium4 \
+        "--with-specs=%{m32:%{!D_WIN32_WINNT*:-D_WIN32_WINNT=0x0501}}" \
         --target=$ARCH \
         --host=$ARCH \
         --enable-static \
@@ -465,7 +506,6 @@ RUN cat $PREFIX/src/crossgcc-*.patch | patch -d/dl/gcc -p1 \
         --disable-libstdcxx-verbose \
         --disable-dependency-tracking \
         --disable-lto \
-        --disable-multilib \
         --disable-nls \
         --disable-win32-registry \
         --enable-mingw-wildcard \
@@ -494,9 +534,9 @@ RUN $ARCH-gcc -DEXE=gcc.exe -DCMD=cc \
  && $ARCH-gcc -DEXE=gcc.exe -DCMD="cc -ansi" \
         -Oz -fno-asynchronous-unwind-tables -Wl,--gc-sections -s -nostdlib \
         -o $PREFIX/bin/c89.exe $PREFIX/src/alias.c -lkernel32 \
- && printf '%s\n' addr2line ar as c++filt cpp dlltool dllwrap elfedit g++ \
+ && printf '%s\n' addr2line ar as c++filt cpp dlltool dllwrap g++ \
       gcc gcc-ar gcc-nm gcc-ranlib gcov gcov-dump gcov-tool gendef gfortran \
-      ld nm objcopy objdump ranlib readelf size strings strip uuidgen widl \
+        ld nm objcopy objdump ranlib size strings strip uuidgen widl \
       windmc windres \
     | xargs -I{} -P$(nproc) \
           $ARCH-gcc -DEXE={}.exe -DCMD=$ARCH-{} \
@@ -504,6 +544,46 @@ RUN $ARCH-gcc -DEXE=gcc.exe -DCMD=cc \
             -Wl,--gc-sections -s -nostdlib \
             -o $PREFIX/bin/$ARCH-{}.exe $PREFIX/src/alias.c -lkernel32
 
+# Create i686 tool aliases
+RUN printf '%s\n' addr2line ar c++filt gcc-ar gcc-nm gcc-ranlib gcov \
+        gcov-dump gcov-tool gendef nm objcopy objdump ranlib size strings \
+        strip uuidgen widl windmc \
+    | xargs -I{} -P$(nproc) \
+          $ARCH-gcc -DEXE={}.exe -DCMD=i686-w64-mingw32-{} \
+            -Oz -fno-asynchronous-unwind-tables \
+            -Wl,--gc-sections -s -nostdlib \
+            -o $PREFIX/bin/i686-w64-mingw32-{}.exe \
+            $PREFIX/src/alias.c -lkernel32 \
+ && printf '%s\n' cpp gcc g++ gfortran \
+    | xargs -I{} -P$(nproc) \
+          $ARCH-gcc -DEXE={}.exe -DCMD="i686-w64-mingw32-{} -m32" \
+            -Oz -fno-asynchronous-unwind-tables \
+            -Wl,--gc-sections -s -nostdlib \
+            -o $PREFIX/bin/i686-w64-mingw32-{}.exe \
+            $PREFIX/src/alias.c -lkernel32 \
+ && $ARCH-gcc -DEXE=g++.exe -DCMD="i686-w64-mingw32-c++ -m32" \
+        -Oz -fno-asynchronous-unwind-tables -Wl,--gc-sections -s -nostdlib \
+        -o $PREFIX/bin/i686-w64-mingw32-c++.exe \
+        $PREFIX/src/alias.c -lkernel32 \
+ && $ARCH-gcc -DEXE=as.exe -DCMD="i686-w64-mingw32-as --32" \
+        -Oz -fno-asynchronous-unwind-tables -Wl,--gc-sections -s -nostdlib \
+        -o $PREFIX/bin/i686-w64-mingw32-as.exe \
+        $PREFIX/src/alias.c -lkernel32 \
+ && $ARCH-gcc -DEXE=ld.exe -DCMD="i686-w64-mingw32-ld -m i386pe" \
+        -Oz -fno-asynchronous-unwind-tables -Wl,--gc-sections -s -nostdlib \
+        -o $PREFIX/bin/i686-w64-mingw32-ld.exe \
+        $PREFIX/src/alias.c -lkernel32 \
+ && $ARCH-gcc -DEXE=dlltool.exe \
+        -DCMD="i686-w64-mingw32-dlltool -m i386 --as-flags=--32" \
+        -Oz -fno-asynchronous-unwind-tables -Wl,--gc-sections -s -nostdlib \
+        -o $PREFIX/bin/i686-w64-mingw32-dlltool.exe \
+        $PREFIX/src/alias.c -lkernel32 \
+ && $ARCH-gcc -DEXE=windres.exe \
+        -DCMD="i686-w64-mingw32-windres --target=pe-i386" \
+        -Oz -fno-asynchronous-unwind-tables -Wl,--gc-sections -s -nostdlib \
+        -o $PREFIX/bin/i686-w64-mingw32-windres.exe \
+        $PREFIX/src/alias.c -lkernel32
+
 # Build some extra development tools
 
 FROM cross AS build-gendef

From a70f4913c2c030a86bae1aa82c06d3145e625465 Mon Sep 17 00:00:00 2001
From: Peter0x44 <peter0x44@disroot.org>
Date: Sun, 9 Aug 2026 18:56:42 -0500
Subject: [PATCH 2/2] Default x86 Windows target version in headers

---
 Dockerfile                          |  2 --
 src/mingw-default-win32-winnt.patch | 19 +++++++++++++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)
 create mode 100644 src/mingw-default-win32-winnt.patch

diff --git a/Dockerfile b/Dockerfile
index c7d1181..b6efd3b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -273,7 +273,6 @@ RUN cat $PREFIX/src/gcc-*.patch | patch -d/dl/gcc -p1 \
         --prefix=/bootstrap \
         --with-sysroot=/bootstrap \
         --with-arch-32=pentium4 \
-        "--with-specs=%{m32:%{!D_WIN32_WINNT*:-D_WIN32_WINNT=0x0501}}" \
         --target=$ARCH \
         --enable-static \
         --disable-shared \
@@ -489,7 +488,6 @@ RUN cat $PREFIX/src/crossgcc-*.patch | patch -d/dl/gcc -p1 \
         --with-sysroot=$PREFIX \
         --with-native-system-header-dir=/include \
         --with-arch-32=pentium4 \
-        "--with-specs=%{m32:%{!D_WIN32_WINNT*:-D_WIN32_WINNT=0x0501}}" \
         --target=$ARCH \
         --host=$ARCH \
         --enable-static \
diff --git a/src/mingw-default-win32-winnt.patch b/src/mingw-default-win32-winnt.patch
new file mode 100644
index 0000000..eb75943
--- /dev/null
+++ b/src/mingw-default-win32-winnt.patch
@@ -0,0 +1,19 @@
+headers: default 32-bit x86 to Windows XP
+
+The x86_64 multilib toolchain shares one header tree between its 64-bit
+and 32-bit targets. Keep the configured mingw-w64 default for x86_64 and
+other architectures, but preserve w64devkit's Windows XP default when
+the compiler targets i686. An explicit user definition still takes
+precedence through the existing outer guard.
+
+--- a/mingw-w64-headers/crt/_mingw.h.in
++++ b/mingw-w64-headers/crt/_mingw.h.in
+@@ -255,3 +255,7 @@
+ #ifndef _WIN32_WINNT
+-#define _WIN32_WINNT @DEFAULT_WIN32_WINNT@
++# if defined(__i386__)
++#  define _WIN32_WINNT 0x0501
++# else
++#  define _WIN32_WINNT @DEFAULT_WIN32_WINNT@
++# endif
+ #endif