detect-tcl-headers.patch

Subject: Detect available Tcl headers automatically.
From: Andrew Shadura <bugzilla@tut.by>

--- a/lib/critcl/critcl.tcl
+++ b/lib/critcl/critcl.tcl
@@ -3647,7 +3647,13 @@
 }
 
 proc ::critcl::MinTclVersion {file} {
-    return [GetParam $file mintcl 8.4]
+    set required [GetParam $file mintcl 8.4]
+    foreach version $v::hdrsavailable {
+	if {[package vsatisfies $version $required]} {
+	    return $version
+	}
+    }
+    return $required
 }
 
 proc ::critcl::UsingTk {file} {
@@ -4553,6 +4559,10 @@
     variable v::buildplatform [BuildPlatform]
     variable v::hdrdir	      [file join $mydir critcl_c]
 
+    foreach d [lsort -dict [glob -types {d r} -directory $v::hdrdir -tails tcl*]] {
+	lappend v::hdrsavailable [regsub {^tcl} $d {}]
+    }
+
     # The prefix is based on the package's version. This allows
     # multiple versions of the package to use the same cache without
     # interfering with each. Note that we cannot use 'pid' and similar
@@ -4771,6 +4781,9 @@
 	variable hdrdir          ;# Path. Directory containing the helper
 				  # files of the package. A sub-
 				  # directory of 'mydir', see above.
+	variable hdrsavailable   ;# Headers versions available. Used when
+				  # building against system-provided Tcl
+				  # headers
 	variable prefix          ;# String. The string to start all file names
 				  # generated by the package with. See
 				  # 'Initialize' for our choice and