Patch by Sergei Golovan allows one to find tclConfig.sh in /usr/lib/tcl8.6
and tkConfig.sh in /usr/lib/tk8.6 where they are located in Debian
installation.

--- a/unix/tcl.m4
+++ b/unix/tcl.m4
@@ -94,6 +94,7 @@
 			`ls -d /usr/local/lib 2>/dev/null` \
 			`ls -d /usr/contrib/lib 2>/dev/null` \
 			`ls -d /usr/pkg/lib 2>/dev/null` \
+			`ls -d /usr/lib/tcl8.6 2>/dev/null` \
 			`ls -d /usr/lib 2>/dev/null` \
 			`ls -d /usr/lib64 2>/dev/null` \
 			`ls -d /usr/local/lib/tcl8.6 2>/dev/null` \
@@ -227,6 +228,7 @@
 			`ls -d /usr/local/lib 2>/dev/null` \
 			`ls -d /usr/contrib/lib 2>/dev/null` \
 			`ls -d /usr/pkg/lib 2>/dev/null` \
+			`ls -d /usr/lib/tk8.6 2>/dev/null` \
 			`ls -d /usr/lib 2>/dev/null` \
 			`ls -d /usr/lib64 2>/dev/null` \
 			`ls -d /usr/local/lib/tk8.6 2>/dev/null` \