CMake: Switch to GNUInstallDirs.

CMakeLists.txt

@@ -9,16 +9,11 @@ option(ZLIB_BUILD_EXAMPLES "Enable Zlib Examples" ON)
 option(ZLIB_BUILD_SHARED "Enable building zlib shared library" ON)
 option(ZLIB_BUILD_STATIC "Enable building zlib static library" ON)
 
-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")
-set(INSTALL_PKGCONFIG_DIR "${CMAKE_INSTALL_PREFIX}/share/pkgconfig" CACHE PATH "Installation directory for pkgconfig (.pc) files")
-
 include(CheckTypeSize)
 include(CheckFunctionExists)
 include(CheckIncludeFile)
 include(CheckCSourceCompiles)
+include(GNUInstallDirs)
 enable_testing()
 
 check_include_file(sys/types.h HAVE_SYS_TYPES_H)
@@ -200,26 +195,26 @@ endif()
 if(NOT SKIP_INSTALL_LIBRARIES AND NOT SKIP_INSTALL_ALL )
     if(ZLIB_BUILD_SHARED)
         install(TARGETS zlib
-            RUNTIME DESTINATION "${INSTALL_BIN_DIR}"
-            ARCHIVE DESTINATION "${INSTALL_LIB_DIR}"
-            LIBRARY DESTINATION "${INSTALL_LIB_DIR}" )
+            RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}"
+            ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}"
+            LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}" )
     endif(ZLIB_BUILD_SHARED)
 
     if(ZLIB_BUILD_STATIC)
         install(TARGETS zlibstatic
-            RUNTIME DESTINATION "${INSTALL_BIN_DIR}"
-            ARCHIVE DESTINATION "${INSTALL_LIB_DIR}"
-            LIBRARY DESTINATION "${INSTALL_LIB_DIR}" )
+            RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}"
+            ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}"
+            LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}" )
     endif(ZLIB_BUILD_STATIC)
 endif()
 if(NOT SKIP_INSTALL_HEADERS AND NOT SKIP_INSTALL_ALL )
-    install(FILES ${ZLIB_PUBLIC_HDRS} DESTINATION "${INSTALL_INC_DIR}")
+    install(FILES ${ZLIB_PUBLIC_HDRS} DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}")
 endif()
 if(NOT SKIP_INSTALL_FILES AND NOT SKIP_INSTALL_ALL )
-    install(FILES zlib.3 DESTINATION "${INSTALL_MAN_DIR}/man3")
+    install(FILES zlib.3 DESTINATION "${CMAKE_INSTALL_MANDIR}/man3")
 endif()
 if(NOT SKIP_INSTALL_FILES AND NOT SKIP_INSTALL_ALL )
-    install(FILES ${ZLIB_PC} DESTINATION "${INSTALL_PKGCONFIG_DIR}")
+    install(FILES ${ZLIB_PC} DESTINATION "${CMAKE_INSTALL_LIBDIR}/pkgconfig")
 endif()
 
 #============================================================================