Você precisa instalar o pacote libcurl-dev
para desenvolvimento.
Virtual Package: libcurl-dev
This is a virtual package. See the Debian policy for a definition of virtual packages.
Packages providing libcurl-dev
libcurl4-gnutls-dev
development files and documentation for libcurl (GnuTLS flavour)
libcurl4-nss-dev
development files and documentation for libcurl (NSS flavour)
libcurl4-openssl-dev
development files and documentation for libcurl (OpenSSL flavour)