安装rpm包需要libltdl.so.3

之前安装
# rpm -ivh php-5.1.6-23.2.el5_3.i386.rpm
warning: php-5.1.6-23.2.el5_3.i386.rpm: Header V3 DSA signature: NOKEY, key ID 37017186
error: Failed dependencies:
libgmp.so.3 is needed by php-5.1.6-23.2.el5_3.i386
php-cli = 5.1.6-23.2.el5_3 is needed by php-5.1.6-23.2.el5_3.i386
[root@localhost Workstation]# rpm -ivh php-cli-5.1.6-23.2.el5_3.i386.rpm
warning: php-cli-5.1.6-23.2.el5_3.i386.rpm: Header V3 DSA signature: NOKEY, key ID 37017186
error: Failed dependencies:
libgmp.so.3 is needed by php-cli-5.1.6-23.2.el5_3.i386
提示需要libgmp.so.3 找了好久才查到是需要安装gmp-4.1.4-10.e15.i386.rpm

# rpm -ivh mysql-connector-odbc-3.51.26r1127-1.el5.i386.rpm
warning: mysql-connector-odbc-3.51.26r1127-1.el5.i386.rpm: Header V3 DSA signature: NOKEY, key ID 37017186
error: Failed dependencies:
libltdl.so.3 is needed by mysql-connector-odbc-3.51.26r1127-1.el5.i386
libodbcinst.so.1 is needed by mysql-connector-odbc-3.51.26r1127-1.el5.i386
unixODBC is needed by mysql-connector-odbc-3.51.26r1127-1.el5.i386
请问libltdl.so.3在那个rpm包里？