导入GCDAsyncSocket后报"_SSLSetProtocolVersionMin", referenced from:

Undefined symbols for architecture armv7: 
"_SSLGetBufferedReadSize", referenced from: ___33
-[GCDAsyncSocket flushSSLBuffers]_block_invoke_0 in GCDAsyncSocket.o 
-[GCDAsyncSocket doReadData] in GCDAsyncSocket.o 
"_SSLSetIOFuncs", referenced from:
 -[GCDAsyncSocket ssl_startTLS] in GCDAsyncSocket.o 
"_SSLRead", referenced from: 
-[GCDAsyncSocket flushSSLBuffers] in GCDAsyncSocket.o 
-[GCDAsyncSocket doReadData] in GCDAsyncSocket.o 
"_SSLWrite", referenced from: 
-[GCDAsyncSocket doWriteData] in GCDAsyncSocket.o
 "_SSLClose", referenced from: 
-[GCDAsyncSocket closeWithError:] in GCDAsyncSocket.o 
"_SSLCreateContext", referenced from: 
-[GCDAsyncSocket ssl_startTLS] in GCDAsyncSocket.o
 "_SSLSetEnabledCiphers", referenced from: 
-[GCDAsyncSocket ssl_startTLS] in GCDAsyncSocket.o
 "_SSLSetCertificate", referenced from: 
-[GCDAsyncSocket ssl_startTLS] in GCDAsyncSocket.o 
"_SSLSetConnection", referenced from: 
-[GCDAsyncSocket ssl_startTLS] in GCDAsyncSocket.o 
"_SSLHandshake", referenced from: 
-[GCDAsyncSocket ssl_continueSSLHandshake] in GCDAsyncSocket.o 
"_SSLSetProtocolVersionMax", referenced from: 
-[GCDAsyncSocket ssl_startTLS] in GCDAsyncSocket.o 
"_SSLSetPeerDomainName", referenced from: 
-[GCDAsyncSocket ssl_startTLS] in GCDAsyncSocket.o 
"_SSLSetProtocolVersionMin", referenced from: 
-[GCDAsyncSocket ssl_startTLS] in GCDAsyncSocket.old: symbol(s) not found for architecture armv7clang: error: linker command failed with exit code 1 (use -v to see invocation)

添加下面这两个库就可以了

CFNetwork.framework
Security.framework