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)
@@ -124,12 +133,14 @@ 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 ${PROJECT_NAME} PROPERTY
   INTERFACE_${PROJECT_NAME}_MAJOR_VERSION ${MINIZ_API_VERSION})
@@ -137,6 +148,7 @@ set_property(TARGET ${PROJECT_NAME} APPEND PROPERTY
   COMPATIBLE_INTERFACE_STRING ${PROJECT_NAME}_MAJOR_VERSION
 )
 
+if(INSTALL_PROJECT)
   install(TARGETS ${PROJECT_NAME} EXPORT ${PROJECT_NAME}Targets
     RUNTIME  DESTINATION ${CMAKE_INSTALL_BINDIR}
     ARCHIVE  DESTINATION ${CMAKE_INSTALL_LIBDIR}
@@ -179,6 +191,7 @@ install(
     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")
 
+if(INSTALL_PROJECT)
   install(FILES ${INSTALL_HEADERS} DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/${PROJECT_NAME})
-
+endif()