Improve handling for escaped colons in prerequisite lists.

Fixes Savannah bug #12126 and bug #16545

tests/scripts/features/escape

@@ -54,5 +54,13 @@ run_make_test(undef,
 	      'sharp',
 	      'foo#bar.ext = (foo#bar.ext)');
 
+# Test escaped colons in prerequisites
+# Quoting of backslashes in q!! is kind of messy.
+run_make_test(q!
+foo: foo\\:bar foo\\\\\\:bar foo\\\\\\\\\\:bar
+foo foo\\:bar foo\\\\\\:bar foo\\\\\\\\\\:bar: ; @echo '$@'
+!,
+              '', "foo:bar\nfoo\\:bar\nfoo\\\\:bar\nfoo\n");
+
 # This tells the test driver that the perl test script executed properly.
 1;

tests/scripts/features/se_explicit

@@ -152,5 +152,13 @@ a%l: q1x $$+ q2x ; @echo '$+'
                   '', "q1x bar bar q2x bar bar\n");
 
 
-# This tells the test driver that the perl test script executed properly.
+# Allow patsubst shorthand in second expansion context.
+# Requires the colon to be quoted.  Savannah bug #16545
+run_make_test(q!
+.PHONY: foo.bar
+.SECONDEXPANSION:
+foo: $$(@\\:%=%.bar); @echo '$^'
+!,
+              '', "foo.bar\n");
+
 1;