runtime_loader: allow the ABI version symbol to be local.

Some libraries buildsystems (eg. zlib) somehow prevent the symbol from
being exported. We should fix that, but binaries with missing symbols
are already out there, so we need to handle them in any case.

src/system/runtime_loader/elf_haiku_version.cpp

@@ -211,10 +211,9 @@ analyze_image_haiku_version_and_abi(int fd, image_t* image, elf_ehdr& eheader,
 	// Haiku API version
 	elf_sym* symbol = find_symbol(image,
 		SymbolLookupInfo(B_SHARED_OBJECT_HAIKU_VERSION_VARIABLE_NAME,
-			B_SYMBOL_TYPE_DATA));
+			B_SYMBOL_TYPE_DATA, true));
 	if (symbol != NULL && symbol->st_shndx != SHN_UNDEF
 		&& symbol->st_value > 0
-		&& symbol->Type() == STT_OBJECT
 		&& symbol->st_size >= sizeof(uint32)) {
 		image->api_version
 			= *(uint32*)(symbol->st_value + image->regions[0].delta);

src/system/runtime_loader/elf_symbol_lookup.cpp

@@ -93,8 +93,18 @@ patch_undefined_symbol(image_t* rootImage, image_t* image, const char* name,
 }
 
 
+static bool is_symbol_visible(elf_sym* symbol)
+{
+	if (symbol->Bind() == STB_GLOBAL)
+		return true;
+	if (symbol->Bind() == STB_WEAK)
+		return true;
+	return false;
+}
+
+
 elf_sym*
-find_symbol(image_t* image, const SymbolLookupInfo& lookupInfo)
+find_symbol(image_t* image, const SymbolLookupInfo& lookupInfo, bool allowLocal)
 {
 	if (image->dynamic_ptr == 0)
 		return NULL;
@@ -109,8 +119,7 @@ find_symbol(image_t* image, const SymbolLookupInfo& lookupInfo)
 		elf_sym* symbol = &image->syms[i];
 
 		if (symbol->st_shndx != SHN_UNDEF
-			&& ((symbol->Bind() == STB_GLOBAL)
+			&& (allowLocal || is_symbol_visible(symbol))
-				|| (symbol->Bind() == STB_WEAK))
 			&& !strcmp(SYMNAME(image, symbol), lookupInfo.name)) {
 
 			// check if the type matches

src/system/runtime_loader/elf_symbol_lookup.h

@@ -128,7 +128,8 @@ void		patch_undefined_symbol(image_t* rootImage, image_t* image,
 				const char* name, image_t** foundInImage, void** symbol,
 				int32* type);
 
-elf_sym*	find_symbol(image_t* image, const SymbolLookupInfo& lookupInfo);
+elf_sym*	find_symbol(image_t* image, const SymbolLookupInfo& lookupInfo,
+				bool allowLocal = false);
 status_t	find_symbol(image_t* image, const SymbolLookupInfo& lookupInfo,
 				void** _location);
 status_t	find_symbol_breadth_first(image_t* image,