Extract some full-size raw previews without LibRaw

Not all image/x-nikon-nef will work like this,
so don't claim their MIME type.

tiff-tables.awk

@@ -2,6 +2,22 @@
 BEGIN {
 	FS = ", *"
 	print "// Generated by tiff-tables.awk. DO NOT MODIFY."
+	print ""
+	print "#ifndef TIFF_TABLES_CONSTANTS_ONLY"
+	print "#include <stddef.h>"
+	print "#include <stdint.h>"
+	print ""
+	print "struct tiff_value {"
+	print "\tconst char *name;"
+	print "\tuint16_t value;"
+	print "};"
+	print ""
+	print "struct tiff_entry {"
+	print "\tconst char *name;"
+	print "\tuint16_t tag;"
+	print "\tstruct tiff_value *values;"
+	print "};"
+	print "#endif"
 }
 
 {
@@ -55,8 +71,10 @@ function flushvalues() {
 function flushsection() {
 	if (section) {
 		flushvalues()
-		print "};\n\n" allvalues "static struct tiff_entry " \
+		print "};\n\n" allvalues "#ifndef TIFF_TABLES_CONSTANTS_ONLY"
+		print "static struct tiff_entry " \
 			  sectionsnakecase "_entries[] = {" fields "\n\t{}\n};"
+		print "#endif"
 	}
 }