diff --git a/gitk b/gitk
index bc9efa1..a101b07 100755
--- a/gitk
+++ b/gitk
@@ -13,13 +13,6 @@ package require Tk
 ##
 ## Enabling platform-specific code paths
 
-proc is_MacOSX {} {
-	if {[tk windowingsystem] eq {aqua}} {
-		return 1
-	}
-	return 0
-}
-
 proc is_Windows {} {
 	if {$::tcl_platform(platform) eq {windows}} {
 		return 1
@@ -27,36 +20,16 @@ proc is_Windows {} {
 	return 0
 }
 
-set _iscygwin {}
-proc is_Cygwin {} {
-	global _iscygwin
-	if {$_iscygwin eq {}} {
-		if {[string match "CYGWIN_*" $::tcl_platform(os)]} {
-			set _iscygwin 1
-		} else {
-			set _iscygwin 0
-		}
-	}
-	return $_iscygwin
-}
-
 ######################################################################
 ##
 ## PATH lookup
 
-set _search_path {}
-proc _which {what args} {
-	global env _search_exe _search_path
-
-	if {$_search_path eq {}} {
-		if {[is_Cygwin] && [regexp {^(/|\.:)} $env(PATH)]} {
-			set _search_path [split [exec cygpath \
-				--windows \
-				--path \
-				--absolute \
-				$env(PATH)] {;}]
-			set _search_exe .exe
-		} elseif {[is_Windows]} {
+if {[is_Windows]} {
+	set _search_path {}
+	proc _which {what args} {
+		global env _search_exe _search_path
+
+		if {$_search_path eq {}} {
 			set gitguidir [file dirname [info script]]
 			regsub -all ";" $gitguidir "\\;" gitguidir
 			set env(PATH) "$gitguidir;$env(PATH)"
@@ -65,81 +38,78 @@ proc _which {what args} {
 			set _search_path [lsearch -all -inline -not -exact \
 				$_search_path ""]
 			set _search_exe .exe
-		} else {
-			set _search_path [split $env(PATH) :]
-			set _search_exe {}
 		}
-	}
 
-	if {[is_Windows] && [lsearch -exact $args -script] >= 0} {
-		set suffix {}
-	} else {
-		set suffix $_search_exe
-	}
+		if {[lsearch -exact $args -script] >= 0} {
+			set suffix {}
+		} else {
+			set suffix $_search_exe
+		}
 
-	foreach p $_search_path {
-		set p [file join $p $what$suffix]
-		if {[file exists $p]} {
-			return [file normalize $p]
+		foreach p $_search_path {
+			set p [file join $p $what$suffix]
+			if {[file exists $p]} {
+				return [file normalize $p]
+			}
 		}
+		return {}
 	}
-	return {}
-}
 
-proc sanitize_command_line {command_line from_index} {
-	set i $from_index
-	while {$i < [llength $command_line]} {
-		set cmd [lindex $command_line $i]
-		if {[file pathtype $cmd] ne "absolute"} {
-			set fullpath [_which $cmd]
-			if {$fullpath eq ""} {
-				throw {NOT-FOUND} "$cmd not found in PATH"
+	proc sanitize_command_line {command_line from_index} {
+		set i $from_index
+		while {$i < [llength $command_line]} {
+			set cmd [lindex $command_line $i]
+			if {[file pathtype $cmd] ne "absolute"} {
+				set fullpath [_which $cmd]
+				if {$fullpath eq ""} {
+					throw {NOT-FOUND} "$cmd not found in PATH"
+				}
+				lset command_line $i $fullpath
 			}
-			lset command_line $i $fullpath
-		}
 
-		# handle piped commands, e.g. `exec A | B`
-		for {incr i} {$i < [llength $command_line]} {incr i} {
-			if {[lindex $command_line $i] eq "|"} {
-				incr i
-				break
+			# handle piped commands, e.g. `exec A | B`
+			for {incr i} {$i < [llength $command_line]} {incr i} {
+				if {[lindex $command_line $i] eq "|"} {
+					incr i
+					break
+				}
 			}
 		}
+		return $command_line
 	}
-	return $command_line
-}
 
-# Override `exec` to avoid unsafe PATH lookup
+	# Override `exec` to avoid unsafe PATH lookup
 
-rename exec real_exec
+	rename exec real_exec
 
-proc exec {args} {
-	# skip options
-	for {set i 0} {$i < [llength $args]} {incr i} {
-		set arg [lindex $args $i]
-		if {$arg eq "--"} {
-			incr i
-			break
-		}
-		if {[string range $arg 0 0] ne "-"} {
-			break
+	proc exec {args} {
+		# skip options
+		for {set i 0} {$i < [llength $args]} {incr i} {
+			set arg [lindex $args $i]
+			if {$arg eq "--"} {
+				incr i
+				break
+			}
+			if {[string range $arg 0 0] ne "-"} {
+				break
+			}
 		}
+		set args [sanitize_command_line $args $i]
+		uplevel 1 real_exec $args
 	}
-	set args [sanitize_command_line $args $i]
-	uplevel 1 real_exec $args
-}
 
-# Override `open` to avoid unsafe PATH lookup
+	# Override `open` to avoid unsafe PATH lookup
 
-rename open real_open
+	rename open real_open
 
-proc open {args} {
-	set arg0 [lindex $args 0]
-	if {[string range $arg0 0 0] eq "|"} {
-		set command_line [string trim [string range $arg0 1 end]]
-		lset args 0 "| [sanitize_command_line $command_line 0]"
+	proc open {args} {
+		set arg0 [lindex $args 0]
+		if {[string range $arg0 0 0] eq "|"} {
+			set command_line [string trim [string range $arg0 1 end]]
+			lset args 0 "| [sanitize_command_line $command_line 0]"
+		}
+		uplevel 1 real_open $args
 	}
-	uplevel 1 real_open $args
 }
 
 # End of safe PATH lookup stuff
