revert part of 9eda1620b

This probably would've broken native OSX builds

configure.ac

@@ -255,6 +255,7 @@ case $host in
          qt5_prefix=`$BREW --prefix qt5 2>/dev/null`
          if test x$openssl_prefix != x; then
            PKG_CONFIG_PATH="$openssl_prefix/lib/pkgconfig:$PKG_CONFIG_PATH"
+           export PKG_CONFIG_PATH
          fi
          if test x$bdb_prefix != x; then
            CPPFLAGS="$CPPFLAGS -I$bdb_prefix/include"
@@ -262,6 +263,7 @@ case $host in
          fi
          if test x$qt5_prefix != x; then
            PKG_CONFIG_PATH="$qt5_prefix/lib/pkgconfig:$PKG_CONFIG_PATH"
+           export PKG_CONFIG_PATH
          fi
        fi
      else