Allow overriding the default install locations for cmake.

CMakeLists.txt

@@ -3,6 +3,11 @@ set(CMAKE_ALLOW_LOOSE_LOOP_CONSTRUCTS ON)
 
 project(zlib C)
 
+set(INSTALL_BIN_DIR "${CMAKE_INSTALL_PREFIX}/bin" CACHE PATH "Installation directory for executables")
+set(INSTALL_LIB_DIR "${CMAKE_INSTALL_PREFIX}/lib" CACHE PATH "Installation directory for libraries")
+set(INSTALL_INC_DIR "${CMAKE_INSTALL_PREFIX}/include" CACHE PATH "Installation directory for headers")
+set(INSTALL_MAN_DIR "${CMAKE_INSTALL_PREFIX}/share/man" CACHE PATH "Installation directory for manual pages")
+
 if(NOT DEFINED BUILD_SHARED_LIBS)
     option(BUILD_SHARED_LIBS "Build a shared library form of zlib" ON)
 endif()
@@ -165,15 +170,15 @@ endif()
 
 if(NOT SKIP_INSTALL_LIBRARIES AND NOT SKIP_INSTALL_ALL )
     install(TARGETS zlib
-        RUNTIME DESTINATION bin
-        ARCHIVE DESTINATION lib
-        LIBRARY DESTINATION lib )
+        RUNTIME DESTINATION "${INSTALL_BIN_DIR}"
+        ARCHIVE DESTINATION "${INSTALL_LIB_DIR}"
+        LIBRARY DESTINATION "${INSTALL_LIB_DIR}" )
 endif()
 if(NOT SKIP_INSTALL_HEADERS AND NOT SKIP_INSTALL_ALL )
-    install(FILES ${ZLIB_PUBLIC_HDRS} DESTINATION include)
+    install(FILES ${ZLIB_PUBLIC_HDRS} DESTINATION "${INSTALL_INC_DIR}")
 endif()
 if(NOT SKIP_INSTALL_FILES AND NOT SKIP_INSTALL_ALL )
-    install(FILES zlib.3 DESTINATION share/man/man3)
+    install(FILES zlib.3 DESTINATION "${INSTALL_MAN_DIR}/man3")
 endif()
 
 #============================================================================