gdb: Fix building against api level 21

packages/gdb/build.sh

@@ -4,7 +4,6 @@ TERMUX_PKG_DEPENDS="liblzma, libexpat, readline, ncurses, libmpfr"
 TERMUX_PKG_VERSION=8.1
 TERMUX_PKG_SHA256=af61a0263858e69c5dce51eab26662ff3d2ad9aa68da9583e8143b5426be4b34
 TERMUX_PKG_SRCURL=https://mirrors.kernel.org/gnu/gdb/gdb-${TERMUX_PKG_VERSION}.tar.xz
-TERMUX_PKG_API_LEVEL=23
 # gdb can not build with our normal --disable-static: https://sourceware.org/bugzilla/show_bug.cgi?id=15916
 TERMUX_PKG_EXTRA_CONFIGURE_ARGS="
 --with-system-readline

packages/gdb/gdb-gnulib-import-string.in.h.patch

@@ -0,0 +1,15 @@
+diff -u -r ../gdb-8.1/gdb/gnulib/import/string.in.h ./gdb/gnulib/import/string.in.h
+--- ../gdb-8.1/gdb/gnulib/import/string.in.h	2017-06-04 17:51:26.000000000 +0200
++++ ./gdb/gnulib/import/string.in.h	2018-02-01 22:09:38.398023253 +0100
+@@ -183,9 +183,8 @@
+ #if @GNULIB_MEMPCPY@
+ # if ! @HAVE_MEMPCPY@
+ _GL_FUNCDECL_SYS (mempcpy, void *,
+-                  (void *restrict __dest, void const *restrict __src,
+-                   size_t __n)
+-                  _GL_ARG_NONNULL ((1, 2)));
++                  (void * __dest, void const * __src,
++                   size_t __n));
+ # endif
+ _GL_CXXALIAS_SYS (mempcpy, void *,
+                   (void *restrict __dest, void const *restrict __src,