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 = \
 	placeholder.h \
@@ -68,7 +68,7 @@ NEW_LIBTIFF_RELEASE_DATE=$(shell date +"%Y%m%d")
 release:
 	@(echo --- Setting release date to $(NEW_LIBTIFF_RELEASE_DATE) and release version to $(LIBTIFF_VERSION) ---)
 	(rm -f $(top_srcdir)/RELEASE-DATE && echo $(NEW_LIBTIFF_RELEASE_DATE) > $(top_srcdir)/RELEASE-DATE)
-	(rm -f $(top_srcdir)/VERSION && echo $(LIBTIFF_VERSION) > $(top_srcdir)/VERSION)
+	(rm -f $(top_srcdir)/VERSION && echo $(LIBTIFF_VERSION) > $(top_srcdir)/VERSION.txt)
 	(rm -f $(top_builddir)/libtiff/tiffvers.h && sed 's,LIBTIFF_VERSION,$(LIBTIFF_VERSION),;s,LIBTIFF_RELEASE_DATE,$(NEW_LIBTIFF_RELEASE_DATE),;s,LIBTIFF_MAJOR_VERSION,$(LIBTIFF_MAJOR_VERSION),;s,LIBTIFF_MINOR_VERSION,$(LIBTIFF_MINOR_VERSION),;s,LIBTIFF_MICRO_VERSION,$(LIBTIFF_MICRO_VERSION),' $(top_srcdir)/libtiff/tiffvers.h.in > $(top_builddir)/libtiff/tiffvers.h && sed -i 's,@,,g' $(top_builddir)/libtiff/tiffvers.h)
 
 pkgconfigdir = $(libdir)/pkgconfig