Index: head/lang/tcl86/Makefile
===================================================================
--- head/lang/tcl86/Makefile
+++ head/lang/tcl86/Makefile
@@ -56,6 +56,8 @@
 THREADS_CONFIGURE_ENABLE=	threads
 DEBUG_CONFIGURE_ENABLE=	symbols
 
+.include <bsd.port.options.mk>
+
 post-patch:
 	${REINPLACE_CMD} -e \
 	    's|@TCL_BUILD_LIB_SPEC@|@TCL_LIB_SPEC@|; \
@@ -63,6 +65,12 @@
 	     s|@TCL_BUILD_STUB_LIB_PATH@|@TCL_STUB_LIB_PATH@|; \
 	     s|@TCL_SRC_DIR@|${PREFIX}/include/tcl${TCL_VER}|' \
 	     ${PATCH_WRKSRC}/unix/tclConfig.sh.in
+# On FreeBSD 9, pkg-config --cflags tcl can't find zlib.
+.if ${OSVERSION} < 1000000
+	${REINPLACE_CMD} -e \
+	    's|Requires.private: zlib >= 1.2.3||' \
+	    ${PATCH_WRKSRC}/unix/tcl.pc.in
+.endif
 
 post-patch-TCLMAN-off:
 	@${FIND} ${PATCH_WRKSRC}/pkgs -name Makefile.in | ${XARGS} ${REINPLACE_CMD} \