Update mu 1.8.11 => 1.8.13, bugfix release

Changes (since 1.8.11; there was no 1.8.12 release):

* Make server buffer invisible
* Fix mu-headers-toggle-setting user feedback
* Improve browse-url-handlers
* Update some tests, avoid compiler warnings

OK op

mail/mu/Makefile

@@ -1,10 +1,9 @@
 COMMENT=	maildir indexer and searcher with emacs frontend
 
-V=		1.8.11
+V=		1.8.13
 GUILE_V=	3.0
 
 DISTNAME=	mu-$V
-REVISION=	0
 
 FLAVORS=	guile
 FLAVOR ?=

mail/mu/distinfo

@@ -1,2 +1,2 @@
-SHA256 (mu-1.8.11.tar.xz) = 1MHPbddsl9zVPhRo2f+C3B4QIDvmB60ySbp6xBdgNDk=
-SIZE (mu-1.8.11.tar.xz) = 543168
+SHA256 (mu-1.8.13.tar.xz) = INacGpGMHkjm2/U3XYfvPtNYu2s7fQoSDpOoixbVoCY=
+SIZE (mu-1.8.13.tar.xz) = 543696

mail/mu/patches/patch-lib_mu-store_cc

@@ -3,7 +3,7 @@ fix time_t format specifier
 Index: lib/mu-store.cc
 --- lib/mu-store.cc.orig
 +++ lib/mu-store.cc
-@@ -599,7 +599,7 @@ Store::set_dirstamp(const std::string& path, time_t ts
+@@ -603,7 +603,7 @@ Store::set_dirstamp(const std::string& path, time_t ts
  {
  	std::array<char, 2 * sizeof(tstamp) + 1> data{};
  	const auto len = static_cast<size_t>(

mail/mu/patches/patch-lib_utils_mu-utils-format_hh

@@ -1,7 +1,7 @@
 Index: lib/utils/mu-utils-format.hh
 --- lib/utils/mu-utils-format.hh.orig
 +++ lib/utils/mu-utils-format.hh
-@@ -49,7 +49,7 @@ std::string format(const char* frm, ...) __attribute__
+@@ -52,7 +52,7 @@ std::string format(const char* frm, ...) __attribute__
   *
   * @return a formatted string
   */