Add 'build' DSL method.

Disallow processing Environments until configuration is performed.

build_tests/configure/check_c_header_no_fail_set_define.rb

@@ -2,6 +2,8 @@ configure do
   check_c_header "not___found.h", fail: false, set_define: "HAVE_NOT___FOUND_H"
 end
 
-Rscons::Environment.new(echo: :command) do |env|
-  env.Object("simple.o", "simple.c")
+build do
+  Rscons::Environment.new(echo: :command) do |env|
+    env.Object("simple.o", "simple.c")
+  end
 end

build_tests/configure/check_c_header_success_set_define.rb

@@ -2,6 +2,8 @@ configure do
   check_c_header "string.h", set_define: "HAVE_STRING_H"
 end
 
-Rscons::Environment.new(echo: :command) do |env|
-  env.Object("simple.o", "simple.c")
+build do
+  Rscons::Environment.new(echo: :command) do |env|
+    env.Object("simple.o", "simple.c")
+  end
 end

build_tests/configure/check_cfg.rb

@@ -2,6 +2,8 @@ configure do
   check_cfg program: "my-config"
 end
 
-Rscons::Environment.new(echo: :command) do |env|
-  env.Program("myconfigtest", "simple.c")
+build do
+  Rscons::Environment.new(echo: :command) do |env|
+    env.Program("myconfigtest", "simple.c")
+  end
 end

build_tests/configure/check_cfg_package.rb

@@ -2,6 +2,8 @@ configure do
   check_cfg package: "mypackage"
 end
 
-Rscons::Environment.new(echo: :command) do |env|
-  env.Program("myconfigtest", "simple.c")
+build do
+  Rscons::Environment.new(echo: :command) do |env|
+    env.Program("myconfigtest", "simple.c")
+  end
 end

build_tests/configure/error_env_process_before_configure.rb

@@ -0,0 +1,4 @@
+Environment.new do |env|
+  env.Object("simple.o", "simple.cc")
+  env.process
+end

build_tests/configure/multiple_set_define.rb

@@ -3,6 +3,8 @@ configure do
   check_c_header "stdio.h", set_define: "HAVE_STDIO_H"
 end
 
-Rscons::Environment.new(echo: :command) do |env|
-  env.Object("simple.o", "simple.c")
+build do
+  Rscons::Environment.new(echo: :command) do |env|
+    env.Object("simple.o", "simple.c")
+  end
 end