configure: Don't run "export $e" for an empty string

This fixes the side effect of printing the whole environment,
if no --env parameter was provided.

Signed-off-by: Martin Storsjö <martin@martin.st>

diff --git a/configure b/configure
index 2458adb..1ed8956 100755 (executable)
--- a/configure
+++ b/configure
@@ -2543,7 +2543,7 @@ for opt do
     esac
 done
 
-for e in "$env"; do
+for e in $env; do
     eval "export $e"
 done