goto-gcc/goto-ld: reproduce original help output

There are configure scripts that parse the --help output to obtain the
set of supported targets. Without the original output those build
systems are then led to believe that we don't support shared libraries
(which in turn breaks some builds).

Author: tautschnig

src/goto-cc/gcc_mode.cpp

@@ -308,13 +308,6 @@ bool gcc_modet::needs_preprocessing(const std::string &file)
 /// does it.
 int gcc_modet::doit()
 {
-  if(cmdline.isset('?') ||
-     cmdline.isset("help"))
-  {
-    help();
-    return EX_OK;
-  }
-
   native_tool_name=
     compiler_name(cmdline, base_name);
 
@@ -375,6 +368,20 @@ int gcc_modet::doit()
     return EX_OK; // Exit!
   }
 
+  // In hybrid mode, when --help is requested, just reproduce the output of the
+  // original compiler. This is so as not to confuse configure scripts that
+  // depend on particular information (such as the list of supported targets).
+  if(cmdline.isset("help") && produce_hybrid_binary)
+  {
+    help();
+    return run_gcc(compiler);
+  }
+  else if(cmdline.isset('?') || cmdline.isset("help"))
+  {
+    help();
+    return EX_OK;
+  }
+
   if(
     cmdline.isset("dumpmachine") || cmdline.isset("dumpspecs") ||
     cmdline.isset("dumpversion") || cmdline.isset("print-sysroot") ||

src/goto-cc/ld_mode.cpp

@@ -62,16 +62,18 @@ ld_modet::ld_modet(goto_cc_cmdlinet &_cmdline, const std::string &_base_name)
 /// does it.
 int ld_modet::doit()
 {
-  if(cmdline.isset("help"))
-  {
-    help();
-    return EX_OK;
-  }
-
   native_tool_name = linker_name(cmdline, base_name);
 
-  if(cmdline.isset("version") || cmdline.isset("print-sysroot"))
+  // When --help is requested, just reproduce the output of the original
+  // compiler. This is so as not to confuse configure scripts that depend on
+  // particular information (such as the list of supported targets).
+  if(
+    cmdline.isset("help") || cmdline.isset("version") ||
+    cmdline.isset("print-sysroot"))
+  {
+    help();
     return run_ld();
+  }
 
   messaget::eval_verbosity(
     cmdline.get_value("verbosity"), messaget::M_ERROR, gcc_message_handler);