Export fts as a static library for use with musl
musl libc doesn't provide fts, but elfutils and libabigail need it.
Export bionic's fts as a staic library that can be linked into elfutils
and libabigail when compiling against musl.
fts uses recallocarray, which musl doesn't provide, so also include
recallocarray.c in libfts.a.
Requires minor tweaks to fts.c and a wrapper around fts.h to make them
compatible with musl, primarily by providing local definitions of macros
provided in bionic's sys/cdefs.h.
Bug: 190084016
Test: m libfts
Change-Id: Ifac9a59e7504c0c1f5f8a3a5bd3c19a13980b83c
diff --git a/libc/bionic/fts.c b/libc/bionic/fts.c
index dc5ed6b..1287267 100644
--- a/libc/bionic/fts.c
+++ b/libc/bionic/fts.c
@@ -447,7 +447,7 @@
* reasons.
*/
int
-fts_set(FTS *sp __unused, FTSENT *p, int instr)
+fts_set(FTS *sp, FTSENT *p, int instr)
{
if (instr && instr != FTS_AGAIN && instr != FTS_FOLLOW &&
instr != FTS_NOINSTR && instr != FTS_SKIP) {