gnu: boost: Fix ICU support.

* gnu/packages/patches/boost-fix-icu-build.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/boost.scm (boost)[source]: Add the patch.
[arguments]: In the custom configure phase, pass --with-icu=[...]
to ./bootstrap.sh

gnu/local.mk

@@ -578,6 +578,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/bcftools-regidx-unsigned-char.patch	\
   %D%/packages/patches/binutils-loongson-workaround.patch	\
   %D%/packages/patches/blast+-fix-makefile.patch		\
+  %D%/packages/patches/boost-fix-icu-build.patch		\
   %D%/packages/patches/byobu-writable-status.patch		\
   %D%/packages/patches/cairo-CVE-2016-9082.patch			\
   %D%/packages/patches/calibre-no-updates-dialog.patch		\

gnu/packages/boost.scm

@@ -1,6 +1,6 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2014 John Darrington <jmd@gnu.org>
-;;; Copyright © 2014, 2015 Mark H Weaver <mhw@netris.org>
+;;; Copyright © 2014, 2015, 2018 Mark H Weaver <mhw@netris.org>
 ;;; Copyright © 2015 Andreas Enge <andreas@enge.fr>
 ;;; Copyright © 2016 Eric Bavier <bavier@member.fsf.org>
 ;;; Copyright © 2015 Ludovic Courtès <ludo@gnu.org>
@@ -52,7 +52,8 @@ (define-public boost
                     ".tar.bz2"))
               (sha256
                (base32
-                "1aaw48cmimsskzgiclwn0iifp62a5iw9cbqrhfari876af1828ap"))))
+                "1aaw48cmimsskzgiclwn0iifp62a5iw9cbqrhfari876af1828ap"))
+              (patches (search-patches "boost-fix-icu-build.patch"))))
     (build-system gnu-build-system)
     (inputs `(("icu4c" ,icu4c)
               ("zlib" ,zlib)))
@@ -81,8 +82,9 @@ (define-public boost
        (modify-phases %standard-phases
          (delete 'bootstrap)
          (replace 'configure
-           (lambda* (#:key outputs #:allow-other-keys)
+           (lambda* (#:key inputs outputs #:allow-other-keys)
-             (let ((out (assoc-ref outputs "out")))
+             (let ((icu (assoc-ref inputs "icu4c"))
+                   (out (assoc-ref outputs "out")))
                (substitute* '("libs/config/configure"
                               "libs/spirit/classic/phoenix/test/runtest.sh"
                               "tools/build/doc/bjam.qbk"
@@ -96,6 +98,9 @@ (define-public boost
 
                (invoke "./bootstrap.sh"
                        (string-append "--prefix=" out)
+                       ;; Auto-detection looks for ICU only in traditional
+                       ;; install locations.
+                       (string-append "--with-icu=" icu)
                        "--with-toolset=gcc"))))
          (replace 'build
            (lambda* (#:key make-flags #:allow-other-keys)

gnu/packages/patches/boost-fix-icu-build.patch

@@ -0,0 +1,53 @@
+Pass -std=c++11 when compiling files that include the ICU headers.  Without
+this flag, compilation fails and causes Boost's build system to remove ICU
+support.  Note that $(pkg-config --variable=CXXFLAGS icu-uc) includes
+"-std=c++11", but Boost's build system does not use 'pkg-config'.
+
+--- boost_1_66_0/libs/locale/build/Jamfile.v2.orig	2017-12-13 18:56:44.000000000 -0500
++++ boost_1_66_0/libs/locale/build/Jamfile.v2	2018-04-08 15:18:58.673025760 -0400
+@@ -65,8 +65,8 @@
+ 
+ if $(ICU_LINK)
+ {
+-    ICU_OPTS = <include>$(ICU_PATH)/include <linkflags>$(ICU_LINK) <dll-path>$(ICU_PATH)/bin <runtime-link>shared ;
+-    ICU64_OPTS = <include>$(ICU_PATH)/include <linkflags>$(ICU_LINK) <dll-path>$(ICU_PATH)/bin64 <runtime-link>shared ;
++    ICU_OPTS = <include>$(ICU_PATH)/include <cxxflags>-std=c++11 <linkflags>$(ICU_LINK) <dll-path>$(ICU_PATH)/bin <runtime-link>shared ;
++    ICU64_OPTS = <include>$(ICU_PATH)/include <cxxflags>-std=c++11 <linkflags>$(ICU_LINK) <dll-path>$(ICU_PATH)/bin64 <runtime-link>shared ;
+ }
+ else
+ {
+@@ -121,6 +121,7 @@
+     explicit icuuc icudt icuin ;
+ 
+     ICU_OPTS =   <include>$(ICU_PATH)/include 
++      <cxxflags>-std=c++11
+       <library>icuuc/<link>shared/<runtime-link>shared 
+       <library>icudt/<link>shared/<runtime-link>shared 
+       <library>icuin/<link>shared/<runtime-link>shared
+@@ -180,6 +181,7 @@
+     explicit icuuc_64 icudt_64 icuin_64 ;
+ 
+     ICU64_OPTS =   <include>$(ICU_PATH)/include 
++      <cxxflags>-std=c++11
+       <library>icuuc_64/<link>shared/<runtime-link>shared 
+       <library>icudt_64/<link>shared/<runtime-link>shared 
+       <library>icuin_64/<link>shared/<runtime-link>shared
+--- boost_1_66_0/libs/regex/build/Jamfile.v2.orig	2017-12-13 18:56:48.000000000 -0500
++++ boost_1_66_0/libs/regex/build/Jamfile.v2	2018-04-08 15:20:40.865532505 -0400
+@@ -44,7 +44,7 @@
+ 
+    if $(ICU_LINK)
+    {
+-      ICU_OPTS = <include>$(ICU_PATH)/include <linkflags>$(ICU_LINK) <dll-path>$(ICU_PATH)/bin <define>BOOST_HAS_ICU=1 <runtime-link>shared ;
++      ICU_OPTS = <include>$(ICU_PATH)/include <cxxflags>-std=c++11 <linkflags>$(ICU_LINK) <dll-path>$(ICU_PATH)/bin <define>BOOST_HAS_ICU=1 <runtime-link>shared ;
+    }
+    else
+    {
+@@ -78,6 +78,7 @@
+ 
+       ICU_OPTS = 
+          <include>$(ICU_PATH)/include 
++         <cxxflags>-std=c++11
+          <runtime-link>shared:<library>icuuc/<link>shared
+          <runtime-link>shared:<library>icudt/<link>shared
+          <runtime-link>shared:<library>icuin/<link>shared