[GR-16637] Bring our compiler commands more inline with MRI's defaults.

PullRequest: truffleruby/908

Author: aardvark179

lib/truffle/rbconfig-for-mkmf.rb

@@ -136,18 +136,24 @@
   end
 
   for_file = proc do |compiler, flags, opt_command|
-    "#{compiler} #{flags} $< && #{opt_command}"
+    "#{compiler} #{flags} $(CSRCFLAG)$< && #{opt_command}"
   end
 
   for_pipe = proc do |compiler, flags, opt_command|
-    "#{preprocess_ruby} #{cext_dir}/preprocess.rb $< | #{compiler} -I$(<D) #{flags} - -o $@ && #{opt_command}"
+    language_flag = if ('$(CXX)' == compiler)
+                      '-xc++'
+                    else
+                      '-xc'
+                    end
+
+    "#{preprocess_ruby} #{cext_dir}/preprocess.rb $< | #{compiler} -I$(<D) #{flags} #{language_flag} - && #{opt_command}"
   end
 
-  c_flags = '$(INCFLAGS) $(CPPFLAGS) $(CFLAGS) $(COUTFLAG) -xc'
-  cxx_flags = '$(INCFLAGS) $(CPPFLAGS) $(CXXFLAGS) $(COUTFLAG) -xc++'
+  c_flags = '$(INCFLAGS) $(CPPFLAGS) $(CFLAGS) $(COUTFLAG)$@'
+  cxx_flags = '$(INCFLAGS) $(CPPFLAGS) $(CXXFLAGS) $(COUTFLAG)$@'
   opt_command = "#{opt} #{opt_passes} $@ -o $@"
 
-  mkconfig['TRUFFLE_RAW_COMPILE_C'] = for_pipe.call('$(CC)', c_flags, opt_command)
+  mkconfig['TRUFFLE_RAW_COMPILE_C'] = for_file.call('$(CC)', c_flags, opt_command)
   mkconfig['COMPILE_C']   = with_conditional_preprocessing.call(
     for_pipe.call('$(CC)', c_flags, opt_command),
     for_file.call('$(CC)', c_flags, opt_command))

lib/truffle/rbconfig.rb

@@ -61,6 +61,7 @@ module RbConfig
     'build'             => host,
     'build_os'          => host_os_full,
     'configure_args'    => ' ',
+    'COUTFLAG'          => '-o ',
     'CPPFLAGS'          => '',
     'CPPOUTFILE'        => '-o conftest.i',
     'DLDFLAGS'          => '',