Ubuntu 14.04 this works great. OSX 10.11.6 w/homebrew is another story:
$ composer require edamov/pushok:0.2.3
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.
Problem 1
- Installation request for edamov/pushok 0.2.3 -> satisfiable by edamov/pushok[0.2.3].
- edamov/pushok 0.2.3 requires lib-curl >=7.46.0 -> the requested linked library curl has the wrong version installed or is missing from your system, make sure to have the extension providing it.
Installation failed, reverting ./composer.json to its original content.
$ curl --version
curl 7.53.1 (x86_64-apple-darwin15.6.0) libcurl/7.53.1 OpenSSL/1.0.2k zlib/1.2.5 nghttp2/1.20.0
Protocols: dict file ftp ftps gopher http https imap imaps ldap ldaps pop3 pop3s rtsp smb smbs smtp smtps telnet tftp
Features: IPv6 Largefile NTLM NTLM_WB SSL libz TLS-SRP HTTP2 UnixSockets HTTPS-proxy
$ php --ri curl
curl
cURL support => enabled
cURL Information => 7.43.0
Age => 3
Features
AsynchDNS => Yes
CharConv => No
Debug => No
GSS-Negotiate => No
IDN => No
IPv6 => Yes
krb4 => No
Largefile => Yes
libz => Yes
NTLM => Yes
NTLMWB => Yes
SPNEGO => Yes
SSL => Yes
SSPI => No
TLS-SRP => No
HTTP2 => No
GSSAPI => Yes
KERBEROS5 => Yes
UNIX_SOCKETS => Yes
Protocols => dict, file, ftp, ftps, gopher, http, https, imap, imaps, ldap, ldaps, pop3, pop3s, rtsp, smb, smbs, smtp, smtps, telnet, tftp
Host => x86_64-apple-darwin15.0
SSL Version => SecureTransport
ZLib Version => 1.2.5