eina: Include <unistd.h> for getuid and geteuid functions

Summary: If we do not include unistd.h, we end up with implicit
declaration warnings when compiling

@fix

Signed-off-by: Chris Michael <cp.michael@samsung.com>

src/lib/eina/eina_util.c

@@ -21,6 +21,7 @@
 #endif
 
 #include <stdlib.h>
+#include <unistd.h>
 #ifdef _WIN32
 # include <string.h>
 #endif