http://bugs.gentoo.org/331979

patch by William Throwe <wthrowe@mit.edu>

The problem is that a failed match() resets the RSTART variable used to
extract filename_no_gz (visible in the trailing context of the patch),
so it is important that no more match() commands are attempted after the
successful one.  Without the scoping, if (for example) the test for .bz2
succeeds, it prevents testing for .lzma, but doesn't prevent testing for
.xz.  The failing .xz test causes RSTART to be set to zero so
filename_no_gz becomes the empty string.

--- man-1.6f/src/makewhatis.sh
+++ man-1.6f/src/makewhatis.sh
@@ -234,7 +234,7 @@
 	    find $mandir/${pages}$i/. -name '*' $findarg0 $findarg -print | $AWK '
 
 	    function readline() {
-              if (use_zcat || use_bzcat || use_lzcat || use_xzcat) {
+	      if (use_compression) {
 		result = (pipe_cmd | getline);
 		if (result < 0) {
 		  print "Pipe error: " pipe_cmd " " ERRNO > "/dev/stderr";
@@ -249,7 +249,7 @@
 	    }
 	    
 	    function closeline() {
-              if (use_zcat || use_bzcat || use_lzcat || use_xzcat) {
+	      if (use_compression) {
 		return close(pipe_cmd);
 	      } else {
 		return close(filename);
@@ -263,16 +263,20 @@
 	      if (verbose) {
 		print "adding " filename > "/dev/stderr"
 	      }
-	      
+
 	      use_zcat = match(filename,"\\.Z$") ||
 			 match(filename,"\\.z$") || match(filename,"\\.gz$");
-	      if (!use_zcat)
+	      if (!use_zcat) {
 		use_bzcat = match(filename,"\\.bz2");
-              if(!use_bzcat)
-                use_lzcat = match(filename,"\\.lzma");
-              if(!use_lzcat)
-                use_xzcat = match(filename,"\\.xz");
-              if (use_zcat || use_bzcat || use_lzcat || use_xzcat) {
+		if (!use_bzcat) {
+		  use_lzcat = match(filename,"\\.lzma");
+		  if (!use_lzcat) {
+		    use_xzcat = match(filename,"\\.xz");
+		  }
+		}
+	      }
+	      use_compression = (use_zcat || use_bzcat || use_lzcat || use_xzcat);
+	      if (use_compression) {
 		filename_no_gz = substr(filename, 0, RSTART - 1);
 	      } else {
 		filename_no_gz = filename;
@@ -285,7 +289,7 @@
 		actual_section = section;
 	      }
 	      sub(/\..*/, "", progname);
-              if (use_zcat || use_bzcat || use_lzcat || use_xzcat) {
+	      if (use_compression) {
 		if (use_zcat) {
 		  pipe_cmd = "zcat \"" filename "\"";
                 } else if (use_bzcat) {