Provisional fix for bug 3508 - Persistent storage support breaks Linux compatibility.
Enables libnvmemmory.so to be built and dynamically linked on Linux and rom boot reports persistent storage image created OK, but ROM then crashes.
/* esp.c */
#define ESP_MAX_DEVS 7
typedef void (*espdma_memory_read_write)(void *opaque, uint8_t *buf, int len);
void esp_scsi_attach(void *opaque, BlockDriverState *bd, int id);
void *esp_init(target_phys_addr_t espaddr, int it_shift,
espdma_memory_read_write dma_memory_read,
espdma_memory_read_write dma_memory_write,
void *dma_opaque, qemu_irq irq, qemu_irq *reset);