CMake: fix the install name of the installed shared library.

Author: guyharris

CMakeLists.txt

@@ -68,6 +68,18 @@ set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules)
 #
 project(pcap C)
 
+#
+# Setting CMAKE_MACOSX_RPATH to FALSE causes the installed
+# libpcap.A.dylib to have just libpcap.A.dylib as the install
+# name;  Apple built libpcap with an install_name of /usr/lib/libpcap.A.dylib
+# (back when they still shipped individual system dylibs rather than
+# shipping a pre-built shared library cache, at least), and we do the
+# same with autotools; do the same with CMake.
+#
+if (NOT DEFINED CMAKE_INSTALL_NAME_DIR)
+    set(CMAKE_INSTALL_NAME_DIR ${CMAKE_INSTALL_PREFIX}/lib)
+endif()
+
 #
 # For getting raw lists of --libs and --libs --static information from a
 # pkg-config module.