utools Tcl support (#2005)

* Add perl* utools man page links

Matches other languages, related to commit 9162be4.

* uthreads: explicitly list C as supported

uthreads supports C (pthreads) thread tracing, make this explicit.

Earlier use of -l java and -l none unchanged.

Add the corresponding man page and usage examples.

* Add Tcl support for ucalls / uflow / uobjnew / ustat

For some reason we need to use proc__args instead of proc__entry
in uflow.py to get similar results as with e.g. Python.
diff --git a/tools/lib/ustat.py b/tools/lib/ustat.py
index 7ac0967..3661a14 100755
--- a/tools/lib/ustat.py
+++ b/tools/lib/ustat.py
@@ -5,7 +5,7 @@
 #        method calls, class loads, garbage collections, and more.
 #        For Linux, uses BCC, eBPF.
 #
-# USAGE: ustat [-l {java,node,perl,php,python,ruby}] [-C]
+# USAGE: ustat [-l {java,node,perl,php,python,ruby,tcl}] [-C]
 #        [-S {cload,excp,gc,method,objnew,thread}] [-r MAXROWS] [-d]
 #        [interval [count]]
 #
@@ -132,7 +132,7 @@
             formatter_class=argparse.RawDescriptionHelpFormatter,
             epilog=examples)
         parser.add_argument("-l", "--language",
-            choices=["java", "node", "perl", "php", "python", "ruby"],
+            choices=["java", "node", "perl", "php", "python", "ruby", "tcl"],
             help="language to trace (default: all languages)")
         parser.add_argument("-C", "--noclear", action="store_true",
             help="don't clear the screen")
@@ -190,6 +190,10 @@
                     "load__entry": Category.CLOAD,
                     "raise": Category.EXCP
                     }),
+                "tcl": Probe("tcl", ["tclsh", "wish"], {
+                    "proc__entry": Category.METHOD,
+                    "obj__create": Category.OBJNEW
+                    }),
                 }
 
         if self.args.language: