--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/components/emacs/patches/calc-forms.patch Tue Jan 13 10:04:39 2015 -0700
@@ -0,0 +1,18 @@
+# Prevent uninterruptible infinite loop. This is the fix for
+# 20270656 calc: sign change of hh.mm value puts Emacs into tight loop
+# See components/emacs/README.
+#
+--- emacs-24.3.orig/lisp/calc/calc-forms.el 2013-01-01 13:37:17.000000000 -0700
++++ emacs-24.3/lisp/calc/calc-forms.el 2015-01-02 14:57:36.824358166 -0700
+@@ -271,7 +271,10 @@
+ (m (math-normalize (nth 2 a)))
+ (s (let ((calc-internal-prec (max (- calc-internal-prec 4) 3)))
+ (math-normalize (nth 3 a)))))
+- (if (math-negp h)
++ (if (or
++ (math-negp h)
++ (and (= h 0) (math-negp m))
++ (and (= h 0) (= m 0) (math-negp s)))
+ (progn
+ (if (math-posp s)
+ (setq s (math-add s -60)