ecore_wl2: EFL Wayland Build on FreeBSD

This enables a user to build EFL with wayland support enabled
on FreeBSD. It is NOT functioning, but everything starts at
some point.

This requires also linking against -lepoll-shim.
Meson arguments:
-Deeze=false -Dv4l2=false -Dfb=false -Ddrm=false -Dwl=true \
-Dsystemd=false

@fix T8659

src/lib/ecore_wl2/ecore_wl2_buffer.c

@@ -17,7 +17,26 @@
 #include <sys/mman.h>
 #include <sys/ioctl.h>
 
+#if defined(__linux__)
 #include <linux/dma-buf.h>
+#elif defined(__FreeBSD__)
+/* begin/end dma-buf functions used for userspace mmap. */
+struct dma_buf_sync {
+        __u64 flags;
+};
+
+#define DMA_BUF_SYNC_READ      (1 << 0)
+#define DMA_BUF_SYNC_WRITE     (2 << 0)
+#define DMA_BUF_SYNC_RW        (DMA_BUF_SYNC_READ | DMA_BUF_SYNC_WRITE)
+#define DMA_BUF_SYNC_START     (0 << 2)
+#define DMA_BUF_SYNC_END       (1 << 2)
+#define DMA_BUF_SYNC_VALID_FLAGS_MASK \
+        (DMA_BUF_SYNC_RW | DMA_BUF_SYNC_END)
+
+#define DMA_BUF_BASE            'b'
+#define DMA_BUF_IOCTL_SYNC      _IOW(DMA_BUF_BASE, 0, struct dma_buf_sync)
+#endif
+
 #include "linux-dmabuf-unstable-v1-client-protocol.h"
 
 #define SYM(lib, xx)               \