build.sh

#!/usr/bin/env bash

gcc ./dyldfunclookuphelper.c /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/lib/dylib1.o \
    -shared -o ./libdyldfunclookuphelper.dylib -target x86_64-apple-macos10.7

# OR (untested)
#ld /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/lib/dylib1.o \
#   -dylib -o ./libdyldfunclookuphelper.dylib -alias __dyld_func_lookup _dyld_func_lookup_helper

g++ ./example.cpp -ldyldfunclookuphelper -L.

dyldfunclookuphelper.c

int _dyld_func_lookup(const char *name, void **address);

int dyld_func_lookup_helper(const char *name, void **address) {
  return _dyld_func_lookup(name, address);
}

example.cpp

#include <cstdio>

extern "C" int dyld_func_lookup_helper(const char *file, void **address);

int main() {
  void *origdlsym;

  if (!dyld_func_lookup_helper("__dyld_dlsym", &origdlsym)) {
    printf("dyld_func_lookup_helper failed\n");
  } else {
    printf("origdlsym: %lx", origdlsym);
  }
}