Unable to compile on Arch Linux with new OpenSSL version

[maufl]

Hi, I'm trying to compile this library on Arch Linux (rolling release). The system OpenSSL library has version 1.1 but and the compilation fails with

/home/maufl/Code/ccnx/PARC/Libparc/parc/security/parc_SymmetricKeySigner.c: In function ‘_hmacCreate’:
/home/maufl/Code/ccnx/PARC/Libparc/parc/security/parc_SymmetricKeySigner.c:108:48: error: invalid application of ‘sizeof’ to incomplete type ‘HMAC_CTX {aka struct hmac_ctx_st}’
     HMAC_CTX *ctx = parcMemory_Allocate(sizeof(HMAC_CTX) * 2);

There is also a legacy OpenSSL library 1.0 which is installed but I'm not sure how to properly instruct CMake to use it. I tried various combinations of -DOPENSSL_ROOT and -DOPENSSL_INCLUDE and so forth but I always receive an error like

[ 83%] Linking C executable test_parc_X509Certificate                                 
../../libparc.a(parc_Security.c.o): In function `_getThreadId':                                     
parc_Security.c:(.text+0x140): undefined reference to `CRYPTO_THREADID_set_numeric'                                    
../../libparc.a(parc_Security.c.o): In function `_initLocks':                              
parc_Security.c:(.text+0x151): undefined reference to `CRYPTO_num_locks'                                                                                  
parc_Security.c:(.text+0x19f): undefined reference to `CRYPTO_num_locks'                  
parc_Security.c:(.text+0x247): undefined reference to `CRYPTO_num_locks'                        
parc_Security.c:(.text+0x258): undefined reference to `CRYPTO_THREADID_set_callback'     
parc_Security.c:(.text+0x264): undefined reference to `CRYPTO_set_locking_callback'                                    
../../libparc.a(parc_Security.c.o): In function `_finiLocks':                              
parc_Security.c:(.text+0x27e): undefined reference to `CRYPTO_set_locking_callback'                                    
parc_Security.c:(.text+0x2b6): undefined reference to `CRYPTO_num_locks'                                               
../../libparc.a(parc_Security.c.o): In function `parcSecurity_Init':                            
parc_Security.c:(.text+0x3ef): undefined reference to `OPENSSL_add_all_algorithms_noconf'
parc_Security.c:(.text+0x3f4): undefined reference to `ERR_load_crypto_strings'
../../libparc.a(parc_Security.c.o): In function `parcSecurity_Fini':
parc_Security.c:(.text+0x55c): undefined reference to `EVP_cleanup'
parc_Security.c:(.text+0x561): undefined reference to `ERR_free_strings'

I try to install this library to satisfy the dependencies of libccnx-common.