add musl-fts as dependency

README.md

@@ -34,6 +34,9 @@ Mac OS X, iOS, watchOS (untested) and tvOS (untested)
 SDKs with .tdb stubs (>= Xcode 7) require the TAPI library to be installed.  
 => https://github.com/tpoechtrager/apple-libtapi
 
+musl-libc based systems require the musl-fts library to be installed.
+=> https://github.com/pullmoll/musl-fts
+
 Optional, but recommended:
 
 `llvm-devel`               (For Link Time Optimization Support)  

cctools/configure.ac

@@ -314,6 +314,12 @@ LDFLAGS=$ORIGLDFLAGS
 CHECK_LLVM
 LDFLAGS="$LDFLAGS $LTO_RPATH"
 
+### Check for libfts (musl) ###
+
+AC_CHECK_LIB([fts],[fts_open],[
+  AC_CHECK_HEADERS([fts.h], [FTS_LIB=-lfts])], [])
+AC_SUBST(FTS_LIB)
+
 ### Check for libxar ###
 
 if test "x$LLVM_CONFIG" != "xno"; then

cctools/libstuff/Makefile.am

@@ -2,6 +2,8 @@ noinst_LTLIBRARIES = libstuff.la
 
 libstuff_la_CFLAGS = -I$(top_srcdir)/include -I$(top_srcdir)/include/foreign -D__DARWIN_UNIX03 $(WARNINGS) $(LTO_DEF) -DPROGRAM_PREFIX="\"$(PROGRAM_PREFIX)\"" $(ENDIAN_FLAG)
 
+libstuff_la_LDFLAGS = $(FTS_LIB)
+
 libstuff_la_SOURCES =  \
 	allocate.c  \
 	apple_version.c  \