standalone: update to musl version 1.1.16

This release fixes a serious under-allocation bug in regexec due to
integer overflow (CVE-2016-8859) and related issues.

http://www.openwall.com/lists/musl/2017/01/03/1

GNUmakefile

@@ -8,8 +8,8 @@ DEPS_BIN = $(DEPS_PREFIX)/bin
 DEPS_LIB = $(DEPS_PREFIX)/lib
 DEPS_INC = $(DEPS_PREFIX)/include
 
-LIBMUSL = musl-1.1.15
-LIBMUSL_SHA1 = 027c3ae2182fa53c2b554ca98a28dc5cfca4b2c3
+LIBMUSL = musl-1.1.16
+LIBMUSL_SHA1 = 5c2204b31b1ee08a01d4d3e34c6e46f6256bdac8
 
 LIBNCURSES = ncurses-6.0
 LIBNCURSES_SHA1 = acd606135a5124905da770803c05f1f20dd3b21c