Define findModulesAndOffsets() unconditionally to unbreak build

[krytarowski]

Summary

With the following commit:

http://reviews.llvm.org/D12884
[Windows] Symbolize with llvm-symbolizer instead of dbghelp in a self-host

build has been broken on NetBSD.

[joerg]

As mentioned on IRC, this is clearly not correct. There are two unrelated issues in the tree right now:
(1) backtrace(3) doesn't correctly link against libexecinfo on FreeBSD and NetBSD.
(2) Lack of backtrace(3) results in a broken build due to missing findModulesAndOffsets.

This patch addresses neither.

[krytarowski]

In D14482#284727, @joerg wrote:

(2) Lack of backtrace(3) results in a broken build due to missing findModulesAndOffsets.

How to solve (2) differently?

[krytarowski]

@rnk fixed it upstream the same way

[joerg]

It's not fixed, it's just no longer breaking the build. The condition used is still completely wrong.

[rnk]

Sorry, I missed this a week ago. I only responded to the email I got directly about my patch.

Joerg, feel free to fix the ifdef soup.

lib/Support/Unix/Signals.inc

 /// AddSignalHandler - Add a function to be called when a signal is delivered
 /// to the process.  The handler can have a cookie passed to it to identify
 /// what instance of the handler it is.
 void llvm::sys::AddSignalHandler(void (*FnPtr)(void *), void *Cookie) {
   CallBacksToRun->push_back(std::make_pair(FnPtr, Cookie));
   RegisterHandlers();
 }
 
-#if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
-
-#if HAVE_LINK_H && (defined(__linux__) || defined(__FreeBSD__) ||              \
+#if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES) && \
+     HAVE_LINK_H && (defined(__linux__) || defined(__FreeBSD__) ||              \
                     defined(__FreeBSD_kernel__) || defined(__NetBSD__))
 struct DlIteratePhdrData {
   void **StackTrace;
   int depth;
   bool first;
   const char **modules;
   intptr_t *offsets;
   const char *main_exec_name;

 #else
 static bool findModulesAndOffsets(void **StackTrace, int Depth,
                                   const char **Modules, intptr_t *Offsets,
                                   const char *MainExecutableName,
                                   StringSaver &StrPool) {
   return false;
 }
 #endif
-#endif // defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
 
 // PrintStackTrace - In the case of a program crash or fault, print out a stack
 // trace so that the user has an indication of why and where we died.
 //
 // On glibc systems we have the 'backtrace' function, which works nicely, but
 // doesn't demangle symbols.
 void llvm::sys::PrintStackTrace(raw_ostream &OS) {
 #if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)