Fix macos build script

build

@@ -4,15 +4,14 @@
 if [ "$1" == "32" ]; then
     CC="$(which gcc) -m32"
     CXX="$(which g++) -m32"
-    export CC
-    export CXX
+    export CC CXX
     shift
     opt="--host=i686-pc-linux-gnu --target=i686-pc-linux-gnu"
 fi
 
 # Jonathan C dev hack: refer to LNKDOS16 in /usr/src/doslib
-doslib=
-if [ -d "/usr/src/doslib" ]; then doslib="/usr/src/doslib"; fi
+doslib=""
+if [ -d /usr/src/doslib ]; then doslib="/usr/src/doslib"; fi
 
 if [ -n "${doslib}" ]; then
     if [ -x "${doslib}/tool/linker/linux-host/lnkdos16" ]; then
@@ -29,15 +28,15 @@ fi
 chmod +x vs/sdl/build-scripts/strip_fPIC.sh
 
 # prefer to compile against our own copy of SDL 1.x
-echo Compiling our internal SDL 1.x
+echo "Compiling our internal SDL 1.x"
 (cd vs/sdl && ./build-dosbox.sh) || exit 1
 
 # prefer to compile against our own copy of SDLnet 1.x
-echo Compiling our internal SDLnet 1.x
+echo "Compiling our internal SDLnet 1.x"
 (cd vs/sdlnet && ./build-dosbox.sh) || exit 1
 
 # now compile ourself
-echo Compiling DOSBox-X
+echo "Compiling DOSBox-X"
 chmod +x configure
 ./configure --enable-debug --prefix=/usr "${@}" "${opt}" || exit 1
 make -j3 || exit 1