Improved cmake subproject support

- Added code to determine whether this is a standalone project or included by other projects.
- Added option INSTALL_PROJECT to enable/disable install project.
- Replaced CMAKE_BINARY_DIR to CMAKE_CURRENT_BINARY_DIR.

CMakeLists.txt

@@ -7,7 +7,11 @@ else()
   project(miniz C)
 endif()
 
-include(GNUInstallDirs)
+# determine whether this is a standalone project or included by other projects
+set(MINIZ_STANDALONE_PROJECT OFF)
+if (CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_SOURCE_DIR)
+  set(MINIZ_STANDALONE_PROJECT ON)
+endif ()
 
 set(MINIZ_API_VERSION 2)
 set(MINIZ_MINOR_VERSION 1)
@@ -23,14 +27,19 @@ if(CMAKE_BUILD_TYPE STREQUAL "")
 CMAKE_C_FLAGS used) Debug Release RelWithDebInfo MinSizeRel." FORCE)
 endif ()
 
-option(BUILD_EXAMPLES "Build examples" ON)
+option(BUILD_EXAMPLES "Build examples" ${MINIZ_STANDALONE_PROJECT})
 option(BUILD_FUZZERS "Build fuzz targets" OFF)
 option(AMALGAMATE_SOURCES "Amalgamate sources into miniz.h/c" OFF)
 option(BUILD_HEADER_ONLY "Build a header-only version" OFF)
 option(BUILD_SHARED_LIBS "Build shared library instead of static" ON)
+option(INSTALL_PROJECT "Install project" ${MINIZ_STANDALONE_PROJECT})
 
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/bin)
 
+if(INSTALL_PROJECT)
+  include(GNUInstallDirs)
+endif()
+
 if(BUILD_HEADER_ONLY)
   set(AMALGAMATE_SOURCES ON CACHE BOOL "Build a header-only version" FORCE)
 endif(BUILD_HEADER_ONLY)
@@ -124,11 +133,13 @@ if(NOT BUILD_HEADER_ONLY)
     PRIVATE $<$<C_COMPILER_ID:GNU>:_GNU_SOURCE>)
 
   # pkg-config file
-  configure_file(miniz.pc.in ${CMAKE_BINARY_DIR}/miniz.pc @ONLY)
+  configure_file(miniz.pc.in ${CMAKE_CURRENT_BINARY_DIR}/miniz.pc @ONLY)
 
+  if(INSTALL_PROJECT)
     install(FILES
-    ${CMAKE_BINARY_DIR}/miniz.pc
+      ${CMAKE_CURRENT_BINARY_DIR}/miniz.pc
       DESTINATION ${CMAKE_INSTALL_DATADIR}/pkgconfig)
+  endif()
 endif()
 
 set_property(TARGET ${PROJECT_NAME} PROPERTY
@@ -137,40 +148,41 @@ set_property(TARGET ${PROJECT_NAME} APPEND PROPERTY
   COMPATIBLE_INTERFACE_STRING ${PROJECT_NAME}_MAJOR_VERSION
 )
 
-install(TARGETS ${PROJECT_NAME} EXPORT ${PROJECT_NAME}Targets
+if(INSTALL_PROJECT)
+  install(TARGETS ${PROJECT_NAME} EXPORT ${PROJECT_NAME}Targets
     RUNTIME  DESTINATION ${CMAKE_INSTALL_BINDIR}
     ARCHIVE  DESTINATION ${CMAKE_INSTALL_LIBDIR}
     LIBRARY  DESTINATION ${CMAKE_INSTALL_LIBDIR}
     # users can use <miniz.h> or <miniz/miniz.h>
     INCLUDES DESTINATION include ${CMAKE_INSTALL_INCLUDEDIR}/${PROJECT_NAME}
-)
+  )
 
-include(CMakePackageConfigHelpers)
-write_basic_package_version_file(
+  include(CMakePackageConfigHelpers)
+  write_basic_package_version_file(
     "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}/${PROJECT_NAME}ConfigVersion.cmake"
     VERSION ${MINIZ_VERSION}
     COMPATIBILITY AnyNewerVersion
-)
+  )
 
-export(EXPORT ${PROJECT_NAME}Targets
+  export(EXPORT ${PROJECT_NAME}Targets
     FILE "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}/${PROJECT_NAME}Targets.cmake"
     NAMESPACE ${PROJECT_NAME}::
-)
-configure_file(Config.cmake.in
+  )
+  configure_file(Config.cmake.in
     "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}/${PROJECT_NAME}Config.cmake"
     @ONLY
-)
+  )
 
-set(ConfigPackageLocation ${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME})
-install(EXPORT ${PROJECT_NAME}Targets
+  set(ConfigPackageLocation ${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME})
+  install(EXPORT ${PROJECT_NAME}Targets
     FILE
       ${PROJECT_NAME}Targets.cmake
     NAMESPACE
       ${PROJECT_NAME}::
     DESTINATION
       ${ConfigPackageLocation}
-)
-install(
+  )
+  install(
     FILES
       "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}/${PROJECT_NAME}Config.cmake"
       "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}/${PROJECT_NAME}ConfigVersion.cmake"
@@ -178,7 +190,8 @@ install(
       ${ConfigPackageLocation}
     COMPONENT
       Devel
-)
+  )
+endif()
 
 if(BUILD_EXAMPLES)
   set(EXAMPLE1_SRC_LIST "${CMAKE_CURRENT_SOURCE_DIR}/examples/example1.c")
@@ -250,6 +263,7 @@ endif()
 
 set(INCLUDE_INSTALL_DIR "include")
 
-install(FILES ${INSTALL_HEADERS} DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/${PROJECT_NAME})
-
+if(INSTALL_PROJECT)
+  install(FILES ${INSTALL_HEADERS} DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/${PROJECT_NAME})
+endif()