aports/main/snappy/rtti.patch

From f73b11e87dfbe1cb4862b8ee489679d99534f40b Mon Sep 17 00:00:00 2001
From: Tim Serong <tserong@suse.com>
Date: Wed, 27 Oct 2021 18:49:04 +1100
Subject: [PATCH] Re-enable RTTI (needed in order to subclass Source, etc.)

Commit c98344f in snappy 1.1.9 disabled RTTI, which means the
snappy library no longer exports typeinfo for snappy::Source,
snappy::Sink, ..., so users of the library can't subclass these
classes anymore.

Here's a trivial reproducer:

  #include <snappy-sinksource.h>
  class MySource : snappy::Source {
  public:
    size_t Available() const override { return 0; }
    const char *Peek(size_t *len) override { return NULL; }
    void Skip(size_t n) override {}
  };
  int main(int argc, char **argv) {
    MySource m;
    return 0;
  }

Try `g++ -o snappy-test ./snappy-test.cc -lsnappy` with the above
and the linker will fail with "undefined reference to `typeinfo
for snappy::Source'" if RTTI was disabled in the snappy build.
---
 CMakeLists.txt | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6eef485..755605d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -51,10 +51,6 @@ if(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
   string(REGEX REPLACE "/EH[a-z]+" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /EHs-c-")
   add_definitions(-D_HAS_EXCEPTIONS=0)
-
-  # Disable RTTI.
-  string(REGEX REPLACE "/GR" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /GR-")
 else(MSVC)
   # Use -Wall for clang and gcc.
   if(NOT CMAKE_CXX_FLAGS MATCHES "-Wall")
@@ -81,10 +77,6 @@ else(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
   # Disable C++ exceptions.
   string(REGEX REPLACE "-fexceptions" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-exceptions")
-
-  # Disable RTTI.
-  string(REGEX REPLACE "-frtti" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-rtti")
 endif(MSVC)
 
 # BUILD_SHARED_LIBS is a standard CMake variable, but we declare it here to make