从源码手动编译 PHP 时出现如下错误：

Undefined symbols for architecture x86_64:
  "_PKCS5_PBKDF2_HMAC", referenced from:
      _zif_openssl_pbkdf2 in openssl.o
  "_TLSv1_1_client_method", referenced from:
      _php_openssl_setup_crypto in xp_ssl.o
  "_TLSv1_1_server_method", referenced from:
      _php_openssl_setup_crypto in xp_ssl.o
  "_TLSv1_2_client_method", referenced from:
      _php_openssl_setup_crypto in xp_ssl.o
  "_TLSv1_2_server_method", referenced from:
      _php_openssl_setup_crypto in xp_ssl.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [libs/libphp5.bundle] Error 1

解决办法

MakeFile 里面找到类似下面这一行：

EXTRA_LIBS = -lresolv -lmcrypt -lltdl -liconv-lm -lxml2 -lcurl -lssl -lcrypto

删除所有的 -lssl 和 -lcrypto 然后添加 libssl.dylib 和 libcrypto.dylib 的路径（如果你安装了 brew，那么则是 /usr/local/opt/openssl/lib/），重新运行 make 命令，done。

附上我修改后的 MakeFile EXTRA_LIBS 那一行：

EXTRA_LIBS = -lz -lresolv -lmcrypt -lltdl -lstdc++ -liconv -liconv -lpng -lz -lcurl -lz -lm -lxml2 -lz -licucore -lm -lcurl -lxml2 -lz -licucore -lm -licui18n -licuuc -licudata -licuio -lxml2 -lz -licucore -lm -lxml2 -lz -licucore -lm -lxml2 -lz -licucore -lm -lxml2 -lz -licucore -lm /usr/local/opt/openssl/lib/libssl.dylib /usr/local/opt/openssl/lib/libcrypto.dylib