Avoid masking errors with `export var=val`

Now passes shellcheck.net!

devscripts/wine-py2exe.sh

@@ -14,7 +14,7 @@ if [ ! -d wine-py2exe ]; then
 
     mkdir wine-py2exe
     cd wine-py2exe
-    export WINEPREFIX=`pwd`
+    WINEPREFIX=$(pwd); export WINEPREFIX
 
     axel -a "http://www.python.org/ftp/python/2.7/python-2.7.msi"
     axel -a "http://downloads.sourceforge.net/project/py2exe/py2exe/0.6.9/py2exe-0.6.9.win32-py2.7.exe"
@@ -45,7 +45,7 @@ if [ ! -d wine-py2exe ]; then
     
 else
 
-    export WINEPREFIX="$( cd wine-py2exe && pwd )"
+    WINEPREFIX=$( cd wine-py2exe && pwd ); export WINEPREFIX
 
 fi