fix case-insensitive build
--- a/Makefile.am
+++ b/Makefile.am
@@ -34,7 +34,7 @@ docfiles = \
 	README.md \
 	RELEASE-DATE \
 	TODO \
-	VERSION
+	VERSION.txt

 EXTRA_DIST = \
 	cmake \
@@ -61,7 +61,7 @@ SUBDIRS = port libtiff tools build contrib test doc

 release:
	(rm -f $(top_srcdir)/RELEASE-DATE && echo $(LIBTIFF_RELEASE_DATE) > $(top_srcdir)/RELEASE-DATE)
-	(rm -f $(top_srcdir)/VERSION && echo $(LIBTIFF_VERSION) > $(top_srcdir)/VERSION)
+	(rm -f $(top_srcdir)/VERSION.txt && echo $(LIBTIFF_VERSION) > $(top_srcdir)/VERSION.txt)
	(rm -f $(top_srcdir)/libtiff/tiffvers.h && sed 's,LIBTIFF_VERSION,$(LIBTIFF_VERSION),;s,LIBTIFF_RELEASE_DATE,$(LIBTIFF_RELEASE_DATE),;s,LIBTIFF_MAJOR_VERSION,$(LIBTIFF_MAJOR_VERSION),;s,LIBTIFF_MINOR_VERSION,$(LIBTIFF_MINOR_VERSION),;s,LIBTIFF_MICRO_VERSION,$(LIBTIFF_MICRO_VERSION),' $(top_srcdir)/libtiff/tiffvers.h.in > $(top_srcdir)/libtiff/tiffvers.h)

 pkgconfigdir = $(libdir)/pkgconfig