Unable to compile leveldb with snappy support

I'm trying to build https://github.com/google/leveldb with support for https://github.com/google/snappy compression on mac os x high sierra for later usage in XCode project, I'm walking through standard compilation procedure described in Readme for both projects. This includes building project via cmake for both projects. In case of snappy project the procedure is smooth everything builds and installs flawlessly. However in case of leveldb, I can't make cmake find snappy library that I previously installed through make install. I don't understand how to debug cmake and find the place it looks for libraries.

Any help is appreciated.

Here are results of both builds:

EDIT

Here is an output, it seems that /usr/local/lib is in the list

Another edit

I've tried running cc -DCHECK_FUNCTION_EXISTS=snappy_compress -Wl,-search_paths_first -Wl,-headerpad_max_install_names -o check_snappy_exist CheckFunctionExists.c -lsnappy as per solution provided by sel-fish. But if failed with the following output:

Undefined symbols for architecture x86_64:
  "std::__1::__vector_base_common<true>::__throw_length_error() const", referenced from:
      void std::__1::vector<snappy::SnappySinkAllocator::Datablock, std::__1::allocator<snappy::SnappySinkAllocator::Datablock> >::__push_back_slow_path<snappy::SnappySinkAllocator::Datablock const>(snappy::SnappySinkAllocator::Datablock const&) in libsnappy.a(snappy.cc.o)
      void std::__1::vector<char*, std::__1::allocator<char*> >::__push_back_slow_path<char* const>(char* const&) in libsnappy.a(snappy.cc.o)
  "std::logic_error::logic_error(char const*)", referenced from:
      void std::__1::vector<snappy::SnappySinkAllocator::Datablock, std::__1::allocator<snappy::SnappySinkAllocator::Datablock> >::__push_back_slow_path<snappy::SnappySinkAllocator::Datablock const>(snappy::SnappySinkAllocator::Datablock const&) in libsnappy.a(snappy.cc.o)
      void std::__1::vector<char*, std::__1::allocator<char*> >::__push_back_slow_path<char* const>(char* const&) in libsnappy.a(snappy.cc.o)
  "std::length_error::~length_error()", referenced from:
      void std::__1::vector<snappy::SnappySinkAllocator::Datablock, std::__1::allocator<snappy::SnappySinkAllocator::Datablock> >::__push_back_slow_path<snappy::SnappySinkAllocator::Datablock const>(snappy::SnappySinkAllocator::Datablock const&) in libsnappy.a(snappy.cc.o)
      void std::__1::vector<char*, std::__1::allocator<char*> >::__push_back_slow_path<char* const>(char* const&) in libsnappy.a(snappy.cc.o)
  "std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::resize(unsigned long, char)", referenced from:
      snappy::Uncompress(char const*, unsigned long, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >*) in libsnappy.a(snappy.cc.o)
      snappy::Compress(char const*, unsigned long, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >*) in libsnappy.a(snappy.cc.o)
  "std::terminate()", referenced from:
      ___clang_call_terminate in libsnappy.a(snappy.cc.o)
  "typeinfo for std::length_error", referenced from:
      void std::__1::vector<snappy::SnappySinkAllocator::Datablock, std::__1::allocator<snappy::SnappySinkAllocator::Datablock> >::__push_back_slow_path<snappy::SnappySinkAllocator::Datablock const>(snappy::SnappySinkAllocator::Datablock const&) in libsnappy.a(snappy.cc.o)
      void std::__1::vector<char*, std::__1::allocator<char*> >::__push_back_slow_path<char* const>(char* const&) in libsnappy.a(snappy.cc.o)
  "vtable for __cxxabiv1::__class_type_info", referenced from:
      typeinfo for snappy::Sink in libsnappy.a(snappy-sinksource.cc.o)
      typeinfo for snappy::Source in libsnappy.a(snappy-sinksource.cc.o)
  NOTE: a missing vtable usually means the first non-inline virtual member function has no definition.
  "vtable for __cxxabiv1::__si_class_type_info", referenced from:
      typeinfo for snappy::ByteArraySource in libsnappy.a(snappy-sinksource.cc.o)
      typeinfo for snappy::UncheckedByteArraySink in libsnappy.a(snappy-sinksource.cc.o)
  NOTE: a missing vtable usually means the first non-inline virtual member function has no definition.
  "vtable for std::length_error", referenced from:
      void std::__1::vector<snappy::SnappySinkAllocator::Datablock, std::__1::allocator<snappy::SnappySinkAllocator::Datablock> >::__push_back_slow_path<snappy::SnappySinkAllocator::Datablock const>(snappy::SnappySinkAllocator::Datablock const&) in libsnappy.a(snappy.cc.o)
      void std::__1::vector<char*, std::__1::allocator<char*> >::__push_back_slow_path<char* const>(char* const&) in libsnappy.a(snappy.cc.o)
  NOTE: a missing vtable usually means the first non-inline virtual member function has no definition.
  "operator delete[](void*)", referenced from:
      snappy::Compress(snappy::Source*, snappy::Sink*) in libsnappy.a(snappy.cc.o)
      snappy::SnappySinkAllocator::Deleter(void*, char const*, unsigned long) in libsnappy.a(snappy.cc.o)
  "operator delete(void*)", referenced from:
      snappy::UncompressAsMuchAsPossible(snappy::Source*, snappy::Sink*) in libsnappy.a(snappy.cc.o)
      snappy::Uncompress(snappy::Source*, snappy::Sink*) in libsnappy.a(snappy.cc.o)
      void std::__1::vector<snappy::SnappySinkAllocator::Datablock, std::__1::allocator<snappy::SnappySinkAllocator::Datablock> >::__push_back_slow_path<snappy::SnappySinkAllocator::Datablock const>(snappy::SnappySinkAllocator::Datablock const&) in libsnappy.a(snappy.cc.o)
      void std::__1::vector<char*, std::__1::allocator<char*> >::__push_back_slow_path<char* const>(char* const&) in libsnappy.a(snappy.cc.o)
      snappy::ByteArraySource::~ByteArraySource() in libsnappy.a(snappy-sinksource.cc.o)
      snappy::UncheckedByteArraySink::~UncheckedByteArraySink() in libsnappy.a(snappy-sinksource.cc.o)
  "operator new[](unsigned long)", referenced from:
      snappy::internal::WorkingMemory::GetHashTable(unsigned long, int*) in libsnappy.a(snappy.cc.o)
      snappy::Compress(snappy::Source*, snappy::Sink*) in libsnappy.a(snappy.cc.o)
      snappy::SnappyScatteredWriter<snappy::SnappySinkAllocator>::SlowAppend(char const*, unsigned long) in libsnappy.a(snappy.cc.o)
  "operator new(unsigned long)", referenced from:
      void std::__1::vector<snappy::SnappySinkAllocator::Datablock, std::__1::allocator<snappy::SnappySinkAllocator::Datablock> >::__push_back_slow_path<snappy::SnappySinkAllocator::Datablock const>(snappy::SnappySinkAllocator::Datablock const&) in libsnappy.a(snappy.cc.o)
      void std::__1::vector<char*, std::__1::allocator<char*> >::__push_back_slow_path<char* const>(char* const&) in libsnappy.a(snappy.cc.o)
  "___cxa_allocate_exception", referenced from:
      void std::__1::vector<snappy::SnappySinkAllocator::Datablock, std::__1::allocator<snappy::SnappySinkAllocator::Datablock> >::__push_back_slow_path<snappy::SnappySinkAllocator::Datablock const>(snappy::SnappySinkAllocator::Datablock const&) in libsnappy.a(snappy.cc.o)
      void std::__1::vector<char*, std::__1::allocator<char*> >::__push_back_slow_path<char* const>(char* const&) in libsnappy.a(snappy.cc.o)
  "___cxa_begin_catch", referenced from:
      ___clang_call_terminate in libsnappy.a(snappy.cc.o)
  "___cxa_free_exception", referenced from:
      void std::__1::vector<snappy::SnappySinkAllocator::Datablock, std::__1::allocator<snappy::SnappySinkAllocator::Datablock> >::__push_back_slow_path<snappy::SnappySinkAllocator::Datablock const>(snappy::SnappySinkAllocator::Datablock const&) in libsnappy.a(snappy.cc.o)
      void std::__1::vector<char*, std::__1::allocator<char*> >::__push_back_slow_path<char* const>(char* const&) in libsnappy.a(snappy.cc.o)
  "___cxa_pure_virtual", referenced from:
      vtable for snappy::Sink in libsnappy.a(snappy-sinksource.cc.o)
      vtable for snappy::Source in libsnappy.a(snappy-sinksource.cc.o)
  "___cxa_throw", referenced from:
      void std::__1::vector<snappy::SnappySinkAllocator::Datablock, std::__1::allocator<snappy::SnappySinkAllocator::Datablock> >::__push_back_slow_path<snappy::SnappySinkAllocator::Datablock const>(snappy::SnappySinkAllocator::Datablock const&) in libsnappy.a(snappy.cc.o)
      void std::__1::vector<char*, std::__1::allocator<char*> >::__push_back_slow_path<char* const>(char* const&) in libsnappy.a(snappy.cc.o)
  "___gxx_personality_v0", referenced from:
      snappy::GetUncompressedLength(snappy::Source*, unsigned int*) in libsnappy.a(snappy.cc.o)
      snappy::Compress(snappy::Source*, snappy::Sink*) in libsnappy.a(snappy.cc.o)
      snappy::RawUncompressToIOVec(char const*, unsigned long, iovec const*, unsigned long) in libsnappy.a(snappy.cc.o)
      snappy::RawUncompressToIOVec(snappy::Source*, iovec const*, unsigned long) in libsnappy.a(snappy.cc.o)
      snappy::RawUncompress(char const*, unsigned long, char*) in libsnappy.a(snappy.cc.o)
      snappy::RawUncompress(snappy::Source*, char*) in libsnappy.a(snappy.cc.o)
      snappy::Uncompress(char const*, unsigned long, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >*) in libsnappy.a(snappy.cc.o)
      ...
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Solution

Seems that your linker cannot find /usr/local/lib/libsnappy.a.

Try to run clang -Xlinker -v, make sure that /usr/local/lib exists in the Library search paths:

clang -Xlinker -v

@(#)PROGRAM:ld  PROJECT:ld64-278.4
configured to support archs: armv6 armv7 armv7s arm64 i386 x86_64 x86_64h armv6m armv7k armv7m armv7em (tvOS)
Library search paths:
    /usr/lib
    /usr/local/lib

Usually, it will exist. Then try sudo update_dyld_shared_cache.

Talking about debug cmake, you can use flags like --debug-output:

cmake --debug-output --trace --debug-trycompile ..

UPDATE:

check_library_exists(snappy snappy_compress "" HAVE_SNAPPY)

actually do actions as below, it will try to link snappy and find if the function exists:

cc  -DCHECK_FUNCTION_EXISTS=snappy_compress -Wl,-search_paths_first -Wl,-headerpad_max_install_names -o check_snappy_exist CheckFunctionExists.c -lsnappy

The source of CheckFunctionExists.c you can find here.
I think this will simplify the problem.