From 0fb42229a5bf13170667701ad6cb468d58348007 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Thu, 2 Apr 2020 12:49:10 +0200
Subject: Fix ~host config to only contain cc and bin modules configuration

Also add ~build2 that contains everything (except config.dist.*) to be used
for build system modules.
---
 libbuild2/buildfile                 | 30 ++++++++++++++++++++----------
 libbuild2/cc/module.cxx             |  2 +-
 libbuild2/config/host-config.cxx.in |  1 +
 libbuild2/config/init.cxx           |  9 ++++++---
 libbuild2/functions-regex.cxx       |  3 +++
 5 files changed, 31 insertions(+), 14 deletions(-)

diff --git a/libbuild2/buildfile b/libbuild2/buildfile
index a253ab1..578a4c8 100644
--- a/libbuild2/buildfile
+++ b/libbuild2/buildfile
@@ -45,21 +45,31 @@ libul{build2}: config/{hxx ixx txx cxx}{** -host-config -**.test...} \
                config/cxx{host-config}
 
 # This will of course blow up spectacularly if we are cross-compiling. But
-# let's wait and enjoy the fireworks (and get a sense of why would someone
-# need to cross-compile a build system).
+# let's wait and enjoy the fireworks (and get a sense of why someone would
+# want to cross-compile a build system).
 #
 config/cxx{host-config}: config/in{host-config}
 {
-  # Remove comment lines which could be confused with preprocessor directives
-  # by some lesser compilers.
+  # For the ~host configuration we only want c/cxx/cc and bin that they load.
+  # For ~build2 we want to keep everything except dist.
   #
-  # Also filter out config.install.chroot -- we definitely don't want it
-  # carried through.
+  # We also remove comment lines which could be confused with preprocessor
+  # directives by some lesser compilers.
   #
-  host_config = $regex.replace_lines($config.save(),                    \
-                                     '^ *(#|config.install.chroot).*$', \
-                                     [null],                            \
-                                     return_lines)
+  # For ~build2 also filter out config.install.chroot -- we definitely don't
+  # want it carried through.
+  #
+  build2_config = $regex.replace_lines(                 \
+    $config.save(),                                     \
+    '^ *(#|config\.dist\.|config\.install\.chroot).*$', \
+    [null],                                             \
+    return_lines)
+
+  host_config = $regex.replace_lines(             \
+    $build2_config,                               \
+    '^ *config\.(c[. ]|cxx[. ]|cc[.]|bin[.]).*$', \
+    '$&',                                         \
+    format_no_copy return_lines)
 }
 
 libul{build2}: dist/{hxx ixx txx cxx}{** -**.test...}
diff --git a/libbuild2/cc/module.cxx b/libbuild2/cc/module.cxx
index 2b2604b..a485b46 100644
--- a/libbuild2/cc/module.cxx
+++ b/libbuild2/cc/module.cxx
@@ -89,7 +89,7 @@ namespace build2
             }
           }
 
-          // If cc.core.config is already loaded then use its toolchain id,
+          // If cc.core.guess is already loaded then use its toolchain id,
           // (optional) pattern, and mode to guess an appropriate default
           // (e.g., for {gcc, *-4.9 -m64} we will get g++-4.9 -m64).
           //
diff --git a/libbuild2/config/host-config.cxx.in b/libbuild2/config/host-config.cxx.in
index 2e45c46..9e3e0c2 100644
--- a/libbuild2/config/host-config.cxx.in
+++ b/libbuild2/config/host-config.cxx.in
@@ -8,5 +8,6 @@ namespace build2
     // This is a raw string literal, in case you are unfamiliar.
     //
     extern const char host_config[] = R"###($host_config$)###";
+    extern const char build2_config[] = R"###($build2_config$)###";
   }
 }
diff --git a/libbuild2/config/init.cxx b/libbuild2/config/init.cxx
index 75193bb..f0f4841 100644
--- a/libbuild2/config/init.cxx
+++ b/libbuild2/config/init.cxx
@@ -142,8 +142,11 @@ namespace build2
       return true; // Initialize first (load config.build).
     }
 
+    // host-config.cxx.in
+    //
 #ifndef BUILD2_BOOTSTRAP
-    extern const char host_config[]; // host-config.cxx.in
+    extern const char host_config[];
+    extern const char build2_config[];
 #endif
 
     bool
@@ -251,12 +254,12 @@ namespace build2
 
             if (s[0] != '~')
               load_config_file (f, l);
-            else if (s == "~host")
+            else if (s == "~host" || s == "~build2")
             {
 #ifdef BUILD2_BOOTSTRAP
               assert (false);
 #else
-              istringstream is (host_config);
+              istringstream is (s[1] == 'h' ? host_config : build2_config);
               load_config (is, path_name (s), l);
 #endif
             }
diff --git a/libbuild2/functions-regex.cxx b/libbuild2/functions-regex.cxx
index 48955ae..6a8c83a 100644
--- a/libbuild2/functions-regex.cxx
+++ b/libbuild2/functions-regex.cxx
@@ -555,6 +555,9 @@ namespace build2
     //                containing the unmatched lines and line replacements
     //                seperated with newlines.
     //
+    // Note that if format_no_copy is specified, unmatched lines are not
+    // copied either.
+    //
     f[".replace_lines"] = [](value s,
                              string re,
                              string fmt,
-- 
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