see https://bugs.gentoo.org/725028
remove hardcoded ar
--- a/dlib/Makefile.in
+++ b/dlib/Makefile.in
@@ -3,6 +3,7 @@
 VERSION = @ver@
 SRCDIR = src/
 DESTDIR = 
+AR= @AR@
 CC = @CC@
 CFLAGS = @CFLAGS@ @DEFS@
 LDFLAGS = @LDFLAGS@
@@ -24,7 +25,7 @@ FILES = src/dnet.o src/dhash.o src/dlist.o src/dstrbuf.o src/dutil.o src/dvector
 .PHONY: all clean-all clean distclean install uninstall
 
 all: $(FILES)
-	ar rc libdlib.a $(FILES)
+	$(AR) rc libdlib.a $(FILES)
 
 test:
 	$(CC) $(CFLAGS) -o test test.c libdlib.a -lm
--- a/dlib/configure.in
+++ b/dlib/configure.in
@@ -11,6 +11,7 @@ cwd=`pwd`
 
 # Checks for programs.
 AC_PROG_CC
+AC_PROG_AR
 AC_PROG_MAKE_SET
 
 AC_ARG_WITH(ssl, [  --with-ssl		  force use of TLS/SSL], [use_ssl=$withval], )