If we don't have GCC, fall back on using floor().

Add the closing brace for the function body while we're at it.

Change-Id: I73170fdc0885972dce531b553ff8601cceea182e
Reviewed-on: https://code.wireshark.org/review/5902
Reviewed-by: Guy Harris <guy@alum.mit.edu>

wsutil/floor.c

@@ -30,10 +30,18 @@ long double
 floorl(long double x)
 {
 #ifdef (__GNUC__)
+  /*
+   * Handle platforms where GCC has the builtin but the platform's
+   * headers (including the headers used with GCC!) don't define
+   * floorl() to use it.
+   *
+   * XXX - are there any such platforms?
+   */
   __builtin_floorl(x);
 #else
-#error "The floorl() function is not present on this system and the GNU C"
-#error "compiler (gcc) isn't in use, which can provide one."
+  /* Not perfect, but probably the best workaround available */
+  return floor((double)x);
 #endif
+}
 
 #endif /* !HAVE_FLOORL */