make newline-delimited dynamic linker path file actually work

apparently the original commit was never tested properly, since
getline was only ever reading one line. the intent was to read the
entire file, so use getdelim with the null byte as delimiter as a
cheap way to read a whole file into memory.

src/ldso/dynlink.c

@@ -478,7 +478,7 @@ static struct dso *load_library(const char *name)
 			if (!sys_path) {
 				FILE *f = fopen(ETC_LDSO_PATH, "rbe");
 				if (f) {
-					if (getline(&sys_path, (size_t[1]){0}, f) > 0) {
+					if (getdelim(&sys_path, (size_t[1]){0}, 0, f) > 0) {
 						size_t l = strlen(sys_path);
 						if (l && sys_path[l-1]=='\n')
 							sys_path[l-1] = 0;