You can change the pin that the ks0108 library uses. So rather than having the GLCD Enable pin connected to arduino pin 18 (Analog 1, SDA), you could connect it to another unused pin, and remap the value in the ks0108_Arduino.h
The pins used to control the GLCD are all defined at the top of ks0108_Arduino.h, so you can just modify the EN definition:
/*********************************************************/
/* Configuration for assigning LCD bits to Arduino Pins */
/*********************************************************/
/* Arduino pins used for Commands
* default assignment uses the first five analog pins
*/
#define CSEL1 14 // CS1 Bit // swap pin assignments with CSEL2 if left/right image is reversed
#define CSEL2 15 // CS2 Bit
#define R_W 16 // R/W Bit
#define D_I 17 // D/I Bit
[glow]#define EN 18 // EN Bit[/glow]
//#define RES 19 // Reset Bit // uncomment this to contol LCD reset on this pin