FetchContent should not include cpack (#1307)

* Only install by default if you are the main project
* Silence warnings with newer CMake

Author: koenvandesande

CMakeLists.txt

@@ -15,6 +15,13 @@ SET(VERSION "${HIREDIS_MAJOR}.${HIREDIS_MINOR}.${HIREDIS_PATCH}")
 MESSAGE("Detected version: ${VERSION}")
 
 PROJECT(hiredis LANGUAGES "C" VERSION "${VERSION}")
+
+#Built as a subproject or if it is the main project
+set(MAIN_PROJECT OFF)
+if (CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_SOURCE_DIR)
+    set(MAIN_PROJECT ON)
+endif()
+
 INCLUDE(GNUInstallDirs)
 
 OPTION(BUILD_SHARED_LIBS "Build shared libraries" ON)
@@ -71,31 +78,35 @@ TARGET_INCLUDE_DIRECTORIES(hiredis PUBLIC $<INSTALL_INTERFACE:include> $<BUILD_I
 
 CONFIGURE_FILE(hiredis.pc.in hiredis.pc @ONLY)
 
-set(CPACK_PACKAGE_VENDOR "Redis")
-set(CPACK_PACKAGE_DESCRIPTION "\
-Hiredis is a minimalistic C client library for the Redis database.
-
-It is minimalistic because it just adds minimal support for the protocol, \
-but at the same time it uses a high level printf-alike API in order to make \
-it much higher level than otherwise suggested by its minimal code base and the \
-lack of explicit bindings for every Redis command.
-
-Apart from supporting sending commands and receiving replies, it comes with a \
-reply parser that is decoupled from the I/O layer. It is a stream parser designed \
-for easy reusability, which can for instance be used in higher level language bindings \
-for efficient reply parsing.
-
-Hiredis only supports the binary-safe Redis protocol, so you can use it with any Redis \
-version >= 1.2.0.
-
-The library comes with multiple APIs. There is the synchronous API, the asynchronous API \
-and the reply parsing API.")
-set(CPACK_PACKAGE_HOMEPAGE_URL "https://github.com/redis/hiredis")
-set(CPACK_PACKAGE_CONTACT "michael dot grunder at gmail dot com")
-set(CPACK_DEBIAN_PACKAGE_SHLIBDEPS ON)
-set(CPACK_RPM_PACKAGE_AUTOREQPROV ON)
-
-include(CPack)
+if (MAIN_PROJECT)
+  set(CPACK_PACKAGE_VENDOR "Redis")
+  set(CPACK_PACKAGE_DESCRIPTION "\
+  Hiredis is a minimalistic C client library for the Redis database.
+  
+  It is minimalistic because it just adds minimal support for the protocol, \
+  but at the same time it uses a high level printf-alike API in order to make \
+  it much higher level than otherwise suggested by its minimal code base and the \
+  lack of explicit bindings for every Redis command.
+  
+  Apart from supporting sending commands and receiving replies, it comes with a \
+  reply parser that is decoupled from the I/O layer. It is a stream parser designed \
+  for easy reusability, which can for instance be used in higher level language bindings \
+  for efficient reply parsing.
+  
+  Hiredis only supports the binary-safe Redis protocol, so you can use it with any Redis \
+  version >= 1.2.0.
+  
+  The library comes with multiple APIs. There is the synchronous API, the asynchronous API \
+  and the reply parsing API.")
+  set(CPACK_PACKAGE_HOMEPAGE_URL "https://github.com/redis/hiredis")
+  set(CPACK_PACKAGE_CONTACT "michael dot grunder at gmail dot com")
+  set(CPACK_DEBIAN_PACKAGE_SHLIBDEPS ON)
+  set(CPACK_RPM_PACKAGE_AUTOREQPROV ON)
+
+  if (NOT CPack_CMake_INCLUDED)  
+    include(CPack)
+  endif()
+endif()
 
 INSTALL(TARGETS hiredis
     EXPORT hiredis-targets