custom config checks - close #108

build_tests/configure/custom_config_check.rb

@@ -0,0 +1,26 @@
+configure do
+  custom_check("Checking 'grep' version") do |op|
+    stdout, stderr, status = op.log_and_test_command(%w[grep --version])
+    should_fail = true
+    if status != 0
+      fail_message = "error executing grep"
+    elsif stdout =~ /^grep \(GNU grep\) 1\./
+      fail_message = "too old!"
+      status = 1
+    elsif stdout =~ /^grep \(GNU grep\) 2\./
+      fail_message = "we'll work with it but you should upgrade"
+      status = 1
+      should_fail = false
+      op.store_merge("CPPDEFINES" => "GREP_WORKAROUND")
+    else
+      op.store_append("CPPDEFINES" => "GREP_FULL")
+    end
+    op.complete(status, success_message: "good!", fail_message: fail_message, fail: should_fail)
+  end
+end
+
+build do
+  Environment.new do |env|
+    puts env["CPPDEFINES"]
+  end
+end