New utility: xbps-fbulk - a fast bulk builder for xbps.

This is a modified version of DragonFlyBSD's fastbulk utility, that
has been adapted for xbps/xbps-src and contains multiple improvements
like configurable logging path, skipping building non working packages
(broken/only_for_archs), etc.

A manual page will be pushed soon.

This is still WIP, it needs more changes to support building a customizable
set of packages and other additions.

mk/prog.mk

@@ -3,7 +3,8 @@
 OBJS	?= main.o
 
 BINS = $(BIN)
-MAN ?= $(BIN).8
+MANSECTION ?= 8
+MAN ?= $(BIN).$(MANSECTION)
 
 ifdef BUILD_STATIC
 BINS += $(BIN).static
@@ -27,8 +28,8 @@ ifdef BUILD_STATIC
 	install -m 755 $(BIN).static $(DESTDIR)$(SBINDIR)
 endif
 ifdef MAN
-	install -d $(DESTDIR)$(MANDIR)/man8
-	install -m 644 $(MAN) $(DESTDIR)$(MANDIR)/man8
+	install -d $(DESTDIR)$(MANDIR)/man$(MANSECTION)
+	install -m 644 $(MAN) $(DESTDIR)$(MANDIR)/man$(MANSECTION)
 endif
 
 .PHONY: uninstall
@@ -38,7 +39,7 @@ ifdef BUILD_STATIC
 	-rm -f $(DESTDIR)$(SBINDIR)/$(BIN).static
 endif
 ifdef MAN
-	-rm -f $(DESTDIR)$(MANDIR)/man8/$(MAN)
+	-rm -f $(DESTDIR)$(MANDIR)/man$(MANSECTION)/$(MAN)
 endif
 
 %.o: %.c