m4: Fix building with clang

packages/m4/build.sh

@@ -3,5 +3,3 @@ TERMUX_PKG_DESCRIPTION="Traditional Unix macro processor"
 TERMUX_PKG_VERSION=1.4.18
 TERMUX_PKG_SRCURL=https://mirrors.kernel.org/gnu/m4/m4-${TERMUX_PKG_VERSION}.tar.xz
 TERMUX_PKG_SHA256=f2c1e86ca0a404ff281631bdc8377638992744b175afb806e25871a24a934e07
-# "undefined reference to `__muloti4":
-TERMUX_PKG_CLANG=no

packages/m4/lib-xalloc-oversized.h.patch

@@ -0,0 +1,29 @@
+Fixed "undefined reference to __muloti4".
+
+diff -u -r ../m4-1.4.18/lib/xalloc-oversized.h ./lib/xalloc-oversized.h
+--- ../m4-1.4.18/lib/xalloc-oversized.h	2016-12-31 13:54:42.000000000 +0000
++++ ./lib/xalloc-oversized.h	2018-08-06 14:25:19.420628987 +0000
+@@ -46,23 +46,6 @@
+    positive and N must be nonnegative.  This is a macro, not a
+    function, so that it works correctly even when SIZE_MAX < N.  */
+ 
+-#if 7 <= __GNUC__ || __has_builtin (__builtin_add_overflow_p)
+-# define xalloc_oversized(n, s) \
+-   __builtin_mul_overflow_p (n, s, (__xalloc_count_type) 1)
+-#elif ((5 <= __GNUC__ \
+-        || (__has_builtin (__builtin_mul_overflow) \
+-            && __has_builtin (__builtin_constant_p))) \
+-       && !__STRICT_ANSI__)
+-# define xalloc_oversized(n, s) \
+-   (__builtin_constant_p (n) && __builtin_constant_p (s) \
+-    ? __xalloc_oversized (n, s) \
+-    : ({ __xalloc_count_type __xalloc_count; \
+-         __builtin_mul_overflow (n, s, &__xalloc_count); }))
+-
+-/* Other compilers use integer division; this may be slower but is
+-   more portable.  */
+-#else
+ # define xalloc_oversized(n, s) __xalloc_oversized (n, s)
+-#endif
+ 
+ #endif /* !XALLOC_OVERSIZED_H_ */