Run md5sum on the files to check if you downloaded them correctly.

LibraryPackageSizeMD5
cURL libcurl-light_7.36.0_arm.ipk 240 KB 7a67f25b21a495f5422a4d7055939074
cURL libcurl-secure_7.36.0_arm.ipk 1.4 MB db98b2bf183e7b663e861cef4e58c793
libexif libexif_0.6.20_arm.ipk 66 KB d962df4b066696a5171d8a3f238c56d4
libgdbm libgdbm_1.9.1_arm.ipk 14 KB b4b265553cd2c486aaed1ac39e29691c
libidn libidn_1.28_arm.ipk 76 KB f5747b477f050981f2568a1711b22ae4
Ncurses libncurses_5.7_arm.ipk 151 KB 7e8dca0d73f3016cf2fdb7d937763436
libsqlite3 libsqlite3_3.6.22_arm.ipk 239 KB 8230a4e5216dbae3bfee62f87f3b7707
libsqlite3 libsqlite3_3.7.9_arm.ipk 281 KB daec84674108eea7655cec313296b10a
libz libz_1.2.8_arm.ipk 43 KB be5bb9a9b33d235c4e224e8e86e81cee

Notes

libcurl

cURL groks URLs

This is version 7.36.0. libcurl includes a very handy tool for downloading/uploading data to URIs.

You may choose to download with or without SSL/SSH support. The secure version is linked to OpenSSL 1.0.1g and libssh2 1.4.3 which increases the size of the install.

Both builds of libcurl require libidn and libz. ipks are available above.

"Light" version without SSL/SSH:

bash-2.05$ curl -V
curl 7.36.0 (arm-quantumstep-linux-gnu) libcurl/7.36.0 zlib/1.2.8 libidn/1.28
Protocols: dict file ftp gopher http imap pop3 rtsp smtp telnet tftp
Features: IDN Largefile libz

"Secure" version with SSL/SSH:

bash-2.05$ curl -V
curl 7.36.0 (arm-quantumstep-linux-gnu) libcurl/7.36.0 OpenSSL/1.0.1g zlib/1.2.8 libidn/1.28 libssh2/1.4.3
Protocols: dict file ftp ftps gopher http https imap imaps pop3 pop3s rtsp scp sftp smtp smtps telnet tftp
Features: IDN Largefile NTLM NTLM_WB SSL libz TLS-SRP

Remove any previous curl installations before installing. Install one package.