two fixes for "make install" handling of shared libs

1. don't try to install (and thus build) shared libs when they were
disabled in config.mak

2. ensure that the path for the dynamic linker exists before
attempting to install it.

Makefile

@@ -45,7 +45,7 @@ LDSO_PATHNAME = $(syslibdir)/ld-musl-$(ARCH).so.1
 
 all: $(ALL_LIBS) $(ALL_TOOLS)
 
-install: $(ALL_LIBS:lib/%=$(DESTDIR)$(libdir)/%) $(ALL_INCLUDES:include/%=$(DESTDIR)$(includedir)/%) $(ALL_TOOLS:tools/%=$(DESTDIR)$(bindir)/%) $(DESTDIR)$(LDSO_PATHNAME)
+install: $(ALL_LIBS:lib/%=$(DESTDIR)$(libdir)/%) $(ALL_INCLUDES:include/%=$(DESTDIR)$(includedir)/%) $(ALL_TOOLS:tools/%=$(DESTDIR)$(bindir)/%) $(if $(SHARED_LIBS),$(DESTDIR)$(LDSO_PATHNAME),)
 
 clean:
 	rm -f crt/*.o
@@ -110,6 +110,7 @@ $(DESTDIR)$(includedir)/%: include/%
 	install -D -m 644 $< $@
 
 $(DESTDIR)$(LDSO_PATHNAME): lib/libc.so
+	install -d -m 755 $(DESTDIR)$(syslibdir)
 	ln -sf $(libdir)/libc.so $@ || true
 
 .PRECIOUS: $(CRT_LIBS:lib/%=crt/%)