diff --git a/build.sh b/build.sh
index 38c0e068..ffd1d01b 100755
--- a/build.sh
+++ b/build.sh
@@ -1,13 +1,13 @@
 #!/bin/bash
 
-cflags="-Wall -O3 -g -std=gnu11 -Isrc -DLUA_USE_POPEN"
+cflags="-Wall -O3 -g -std=gnu11 -Isrc"
 lflags="-lSDL2 -lm"
 
 if [[ $* == *windows* ]]; then
   platform="windows"
   outfile="lite.exe"
   compiler="x86_64-w64-mingw32-gcc"
-  cflags="$cflags -Iwinlib/SDL2-2.0.10/x86_64-w64-mingw32/include"
+  cflags="$cflags -DLUA_USE_POPEN -Iwinlib/SDL2-2.0.10/x86_64-w64-mingw32/include"
   lflags="$lflags -Lwinlib/SDL2-2.0.10/x86_64-w64-mingw32/lib"
   lflags="-lmingw32 -lSDL2main $lflags -mwindows -o $outfile res.res"
   x86_64-w64-mingw32-windres res.rc -O coff -o res.res
@@ -15,6 +15,7 @@ else
   platform="unix"
   outfile="lite"
   compiler="gcc"
+  cflags="$cflags -DLUA_USE_POSIX"
   lflags="$lflags -o $outfile"
 fi