Sort $(wildcard) output where needed for reproducible build output.

The order of inclusion of .o files makes a difference in linker output;
not a functional difference, but still a bitwise difference, which annoys
some packagers who would like reproducible builds.

Report and patch by Christoph Berg

Author: tglsfdc

contrib/pg_xlogdump/Makefile

@@ -7,7 +7,7 @@ PROGRAM = pg_xlogdump
 OBJS = pg_xlogdump.o compat.o xlogreader.o rmgrdesc.o \
 	$(RMGRDESCOBJS) $(WIN32RES)
 
-RMGRDESCSOURCES = $(notdir $(wildcard $(top_srcdir)/src/backend/access/rmgrdesc/*desc.c))
+RMGRDESCSOURCES = $(sort $(notdir $(wildcard $(top_srcdir)/src/backend/access/rmgrdesc/*desc.c)))
 RMGRDESCOBJS = $(patsubst %.c,%.o,$(RMGRDESCSOURCES))
 
 EXTRA_CLEAN = $(RMGRDESCSOURCES) xlogreader.c