Version 9.1.

- Drop upstreamed -nauty patch.
- Drop -cbc patch; upstream uses the system Cbc now.
- Add -ecl patch for ecl 20.4.24.

sagemath-sigfpe.patch

@@ -1,16 +1,16 @@
 diff -up src/sage/libs/ecl.pyx.orig src/sage/libs/ecl.pyx
---- src/sage/libs/ecl.pyx.orig	2018-12-22 16:37:08.000000000 -0700
-+++ src/sage/libs/ecl.pyx	2019-01-17 10:00:52.554236288 -0700
-@@ -16,7 +16,7 @@ from __future__ import print_function, a
+--- src/sage/libs/ecl.pyx.orig	2020-07-07 09:07:43.622621879 -0600
++++ src/sage/libs/ecl.pyx	2020-07-09 10:04:16.260992211 -0600
+@@ -15,7 +15,7 @@ Library interface to Embeddable Common L
  #adapted to work with pure Python types.
  
  from libc.stdlib cimport abort
--from libc.signal cimport SIGINT, SIGBUS, SIGSEGV, SIGCHLD
-+from libc.signal cimport SIGINT, SIGBUS, SIGSEGV, SIGCHLD, SIGFPE
+-from libc.signal cimport SIGINT, SIGBUS, SIGSEGV
++from libc.signal cimport SIGINT, SIGBUS, SIGSEGV, SIGFPE
  from libc.signal cimport raise_ as signal_raise
  from posix.signal cimport sigaction, sigaction_t
  cimport cysignals.signals
-@@ -48,9 +48,14 @@ cdef extern from "eclsig.h":
+@@ -47,9 +47,14 @@ cdef extern from "eclsig.h":
      void ecl_sig_off()
      cdef sigaction_t ecl_sigint_handler
      cdef sigaction_t ecl_sigbus_handler
@@ -25,7 +25,7 @@ diff -up src/sage/libs/ecl.pyx.orig src/sage/libs/ecl.pyx
  
  cdef cl_object string_to_object(char * s):
      return ecl_read_from_cstring(s)
-@@ -239,6 +244,7 @@ def init_ecl():
+@@ -232,6 +237,7 @@ def init_ecl():
      global ecl_has_booted
      cdef char *argv[1]
      cdef sigaction_t sage_action[32]
@@ -33,7 +33,7 @@ diff -up src/sage/libs/ecl.pyx.orig src/sage/libs/ecl.pyx
      cdef int i
  
      if ecl_has_booted:
-@@ -258,6 +264,8 @@ def init_ecl():
+@@ -248,6 +254,8 @@ def init_ecl():
      for i in range(1,32):
          sigaction(i, NULL, &sage_action[i])
  
@@ -42,7 +42,7 @@ diff -up src/sage/libs/ecl.pyx.orig src/sage/libs/ecl.pyx
      #initialize ECL
      ecl_set_option(ECL_OPT_SIGNAL_HANDLING_THREAD, 0)
      cl_boot(1, argv)
-@@ -265,8 +273,12 @@ def init_ecl():
+@@ -255,12 +263,19 @@ def init_ecl():
      #save signal handler from ECL
      sigaction(SIGINT, NULL, &ecl_sigint_handler)
      sigaction(SIGBUS, NULL, &ecl_sigbus_handler)
@@ -52,10 +52,7 @@ diff -up src/sage/libs/ecl.pyx.orig src/sage/libs/ecl.pyx
 +    #save ECL's floating point exception flags
 +    ecl_feflags = fegetexcept()
 +
-     #verify that no SIGCHLD handler was installed
-     cdef sigaction_t sig_test
-     sigaction(SIGCHLD, NULL, &sig_test)
-@@ -277,6 +289,9 @@ def init_ecl():
+     #and put the Sage signal handlers back
      for i in range(1,32):
          sigaction(i, &sage_action[i], NULL)
  
@@ -66,8 +63,8 @@ diff -up src/sage/libs/ecl.pyx.orig src/sage/libs/ecl.pyx
      # *SAGE-LIST-OF-OBJECTS* to make it rooted in the reachable tree for the GC
      list_of_objects=cl_cons(Cnil,cl_cons(Cnil,Cnil))
 diff -up src/sage/libs/eclsig.h.orig src/sage/libs/eclsig.h
---- src/sage/libs/eclsig.h.orig	2018-12-22 16:37:08.000000000 -0700
-+++ src/sage/libs/eclsig.h	2019-01-17 10:07:23.060570460 -0700
+--- src/sage/libs/eclsig.h.orig	2020-05-20 16:33:41.000000000 -0600
++++ src/sage/libs/eclsig.h	2020-07-09 10:01:25.618299374 -0600
 @@ -9,25 +9,59 @@
  
  
@@ -129,9 +126,9 @@ diff -up src/sage/libs/eclsig.h.orig src/sage/libs/eclsig.h
  
  /* This MUST be a macro because sig_on() must be in the same
 diff -up src/sage/libs/mpmath/ext_impl.pyx.orig src/sage/libs/mpmath/ext_impl.pyx
---- src/sage/libs/mpmath/ext_impl.pyx.orig	2018-12-22 16:37:08.000000000 -0700
-+++ src/sage/libs/mpmath/ext_impl.pyx	2019-01-17 09:53:24.350937873 -0700
-@@ -164,9 +164,9 @@ opts_double_precision.rounding = ROUND_N
+--- src/sage/libs/mpmath/ext_impl.pyx.orig	2020-05-20 16:33:41.000000000 -0600
++++ src/sage/libs/mpmath/ext_impl.pyx	2020-07-09 10:01:25.620299371 -0600
+@@ -162,9 +162,9 @@ opts_double_precision.rounding = ROUND_N
  opts_mini_prec.prec = 5
  opts_mini_prec.rounding = ROUND_D