Added support to build pkgs in the chroot as normal user via capchroot.

Please read the comment in xbps-src.conf to use it. Fully tested
and working nicely, probably some pkgs will need minimal changes.

--HG--
extra : convert_revision : 820ad6d48aa74cf5b6db1871adea750acccaa82f

xbps-src/libexec/Makefile

@@ -0,0 +1,30 @@
+include ../vars.mk
+
+BINS	= xbps-src-chroot-helper xbps-src-doinst-helper
+
+.PHONY: all
+all:
+	for bin in $(BINS); do						\
+		sed -e	"s|@@XBPS_INSTALL_PREFIX@@|$(PREFIX)|g"		\
+		    -e	"s|@@XBPS_INSTALL_ETCDIR@@|$(ETCDIR)|g"		\
+		    -e  "s|@@XBPS_INSTALL_SHAREDIR@@|$(SHAREDIR)|g"	\
+		    -e  "s|@@XBPS_INSTALL_SBINDIR@@|$(SBINDIR)|g"	\
+			$$bin.sh.in > $$bin;				\
+	done
+
+.PHONY: clean
+clean:
+	-rm -f $(BINS)
+
+.PHONY: install
+install: all
+	install -d $(DESTDIR)$(LIBEXECDIR)
+	for bin in $(BINS); do					\
+		install -m 755 $$bin $(DESTDIR)$(LIBEXECDIR);	\
+	done
+
+.PHONY: uninstall
+uninstall:
+	for bin in $(BINS); do					\
+		rm -f $(DESTDIR)$(LIBEXECDIR)/$$bin;		\
+	done