diff --git a/doc/BUILD-win9x.md b/doc/BUILD-win9x.md
index cb6368d..3066b46 100644
--- a/doc/BUILD-win9x.md
+++ b/doc/BUILD-win9x.md
@@ -107,7 +107,7 @@ building `sdl-1.2.15`. While two tarballs are distributed, only
 ```sh
 ../sdl-1.2.15-src/configure --host=i386-mingw32 --prefix=$HOME/sdl-1.2.15 \
     --enable-shared=no CC=i386-mingw32-gcc \
-    CFLAGS="-ffunction-sections -fdata-sections \
+    CFLAGS="-ffunction-sections -fdata-sections -Os \
     -I$HOME/directx-devel/include -L$HOME/directx-devel/lib"
 ```
 
@@ -123,13 +123,13 @@ WAVE files, support for other audio formats is not required.
     --prefix=$HOME/SDL_mixer-1.2.12 --disable-music-cmd --disable-music-mod \
     --disable-music-ogg --disable-music-mp3 --disable-music-midi \
     --disable-music-flac CC=i386-mingw32-gcc --with-sdl-prefix=$HOME/sdl-1.2.15 \
-    CFLAGS='-ffunction-sections -fdata-sections'
+    CFLAGS='-ffunction-sections -fdata-sections -Os'
 ```
 
 ```sh
 ../SDL_gfx-2.0.26-src/configure --host=i386-mingw32 --enable-shared=no \
     --prefix=$HOME/SDL_gfx-2.0.26 --with-sdl-prefix=$HOME/sdl-1.2.15 \
-    CFLAGS='-ffunction-sections -fdata-sections' \
+    CFLAGS='-ffunction-sections -fdata-sections -Os' \
     CC=i386-mingw32-gcc
 ```
 
@@ -137,6 +137,6 @@ WAVE files, support for other audio formats is not required.
 
 ```sh
 ../enet-1.3.17/configure --prefix=$HOME/enet-1.3.17-win32 \
-    --host=i386-mingw32 CFLAGS='-ffunction-sections -fdata-sections' \
+    --host=i386-mingw32 CFLAGS='-ffunction-sections -fdata-sections -Os' \
     CC=i386-mingw32-gcc
 ```