Most gpg operations fail in FIPS mode on RHEL7 with error: Fatal: can't register GNU Pth with Libgcrypt: Not supported

Issue

• On a RHEL 7 system in FIPS-enforcing mode, all gpg commands that require gpg-agent to request a passphrase fail.
  For example, symmetric encryption fails:

  ~]$ echo inputdata | gpg -ac
  gpg-agent[1921]: Fatal: can't register GNU Pth with Libgcrypt: Not supported
  gpg: can't connect to the agent: End of file
  gpg: problem with the agent: No agent running
  gpg-agent[1923]: Fatal: can't register GNU Pth with Libgcrypt: Not supported
  gpg: can't connect to the agent: End of file
  gpg: problem with the agent: No agent running
  gpg: error creating passphrase: Operation cancelled
  gpg: symmetric encryption of `[stdin]' failed: Operation cancelled
  

  Symmetric encryption succeeds if gpg-agent is bypassed:

  ~]$ echo inputdata | gpg -ac --batch --passphrase mypass
  gpg-agent[1991]: Fatal: can't register GNU Pth with Libgcrypt: Not supported
  gpg: can't connect to the agent: End of file
  gpg: problem with the agent: No agent running
  -----BEGIN PGP MESSAGE-----
  Version: GnuPG v2.0.22 (GNU/Linux)
  
  jA0EBwMCQei+DJHfurhg0j8B3EIY+RowQUJQYjEI9f7ubiUJgIptQ4L+3T34CBaC
  s16DtqS43UlxfQTqB6TJt9uzcQUHFG4sn8WFMcDKBTM=
  =Oa6A
  -----END PGP MESSAGE-----
  

  Key generation fails:

  ~]$ gpg --gen-key
  gpg (GnuPG) 2.0.22; Copyright (C) 2013 Free Software Foundation, Inc.
  This is free software: you are free to change and redistribute it.
  There is NO WARRANTY, to the extent permitted by law.
  
  gpg: keyring `/home/aabb/.gnupg/secring.gpg' created
  Please select what kind of key you want:
     (1) RSA and RSA (default)
     (2) DSA and Elgamal
     (3) DSA (sign only)
     (4) RSA (sign only)
  Your selection? 
  RSA keys may be between 1024 and 4096 bits long.
  What keysize do you want? (2048) 
  Requested keysize is 2048 bits
  Please specify how long the key should be valid.
           0 = key does not expire
        <n>  = key expires in n days
        <n>w = key expires in n weeks
        <n>m = key expires in n months
        <n>y = key expires in n years
  Key is valid for? (0) 
  Key does not expire at all
  Is this correct? (y/N) y
  
  GnuPG needs to construct a user ID to identify your key.
  
  Real name: Aaa Bbb
  Email address: aabb@devnull
  Comment: 
  You selected this USER-ID:
      "Aaa Bbb <aabb@devnull>"
  
  Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? O
  You need a Passphrase to protect your secret key.
  
  gpg-agent[2015]: Fatal: can't register GNU Pth with Libgcrypt: Not supported
  gpg: can't connect to the agent: End of file
  gpg: problem with the agent: No agent running
  gpg-agent[2017]: Fatal: can't register GNU Pth with Libgcrypt: Not supported
  gpg: can't connect to the agent: End of file
  gpg: problem with the agent: No agent running
  gpg: Key generation canceled.