Correction for the fix for Bug 3508 - Persistent storage support breaks Linux compatibility.
A 2nd `make install' will fail attempting to create symlink libnvmemmory.so already created by 1st install.
Install should pre-emptively delete it.
/* 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);