ptx: avoid --format long option falling through into --help

* src/ptx.c (main): Add a 'break' after the --format handling case.
Otherwise it would fall through into the usage case.
* tests/misc/ptx.pl: Add test cases for --format=tex and --format=roff.
* NEWS (Bug fixes): Mention the fix.
Bug introduced in 1999-04-04 commit, SH-UTILS-1_16f-269-gd815c15.
Spotted by coverity (MISSING_BREAK).

NEWS

@@ -31,6 +31,9 @@ GNU coreutils NEWS                                    -*- outline -*-
   ln -sr '' F no longer segfaults.  Now works as expected.
   [bug introduced with the --relative feature in coreutils-8.16]
 
+  ptx --format long option parsing no longer falls through into the --help case.
+  [bug introduced in TEXTUTILS-1_22i]
+
   shuf --repeat no longer dumps core if the input is empty.
   [bug introduced with the --repeat feature in coreutils-8.22]
 

src/ptx.c

@@ -2015,6 +2015,8 @@ main (int argc, char **argv)
         case 10:
           output_format = XARGMATCH ("--format", optarg,
                                      format_args, format_vals);
+          break;
+
         case_GETOPT_HELP_CHAR;
 
         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);

tests/misc/ptx.pl

@@ -33,6 +33,13 @@ my @Tests =
 
 # with coreutils-6.12 and earlier, this would act like "ptx F1 F1"
 ["2files", '-g1 -w1', {IN=>{F1=>"a"}}, {IN=>{F2=>"b"}}, {OUT=>"  a\n  b\n"}],
+
+# with coreutils-8.22 and earlier, the --format long option would
+# fall through into the --help case.
+["format-r", '--format=roff', {IN=>"foo\n"},
+                              {OUT=>".xx \"\" \"\" \"foo\" \"\"\n"}],
+["format-t", '--format=tex',  {IN=>"foo\n"},
+                              {OUT=>"\\xx {}{}{foo}{}{}\n"}],
 );
 
 @Tests = triple_test \@Tests;