CMake: Generate BUILT_WITH list.

Generated:
* GCC/CLANG/MSVC: From CMake C compiler ID.
* GXX/CLANGXX/MSVCXX: From CMake C compiler ID.
* INSTALL: From detection of GNU install program.
* PKGCONFIG: From detection of pkg-config program.
* HDRHISTOGRAM: From detection of libm library.
* ZLIB: From WITH_ZLIB option.
* ZSTD: From WITH_ZSTD option.
* LIBDL: From detection of libdl library.
* PLUGINS: From WITH_PLUGINS option.
* SSL: From WITH_SSL option.
* SASL_SCRAM: From WITH_SASL and WITH_SSL options.
* SASL_CYRUS: From WITH_SASL and WITH_SSL options and WIN32 CMake property.
* LZ4_EXT: From ENABLE_LZ4_EXT option.
* C11THREADS: From C11 threads support detection.
* CRC32C_HW: From CRC32C instruction support detection.
* SNAPPY: Hardcoded, since WITH_SNAPPY is always defined in config.h.in.
* SOCKEM: Hardcoded, since WITH_SNAPPY is always defined in config.h.in.

Not generated: GNULD and LDS

CMakeLists.txt

@@ -18,10 +18,27 @@ option(ENABLE_DEVEL "Enable development asserts, checks, etc" OFF)
 option(ENABLE_REFCNT_DEBUG "Enable refcnt debugging" OFF)
 option(ENABLE_SHAREDPTR_DEBUG "Enable sharedptr debugging" OFF)
 set(TRYCOMPILE_SRC_DIR "${CMAKE_CURRENT_LIST_DIR}/packaging/cmake/try_compile")
+set(BUILT_WITH "CMAKE")
+
+# Toolchain {
+list(APPEND BUILT_WITH "${CMAKE_C_COMPILER_ID}")
+list(APPEND BUILT_WITH "${CMAKE_CXX_COMPILER_ID}")
+# }
+
+# PkgConfig {
+find_package(PkgConfig QUIET)
+if(PkgConfig_FOUND)
+  set(WITH_PKGCONFIG ON)
+  list(APPEND BUILT_WITH "PKGCONFIG")
+endif()
+# }
 
 # LIBM {
 include(CheckLibraryExists)
 check_library_exists(m pow "" WITH_HDRHISTOGRAM)
+if(WITH_HDRHISTOGRAM)
+    list(APPEND BUILT_WITH "HDRHISTOGRAM")
+endif()
 # }
 
 # ZLIB {
@@ -32,6 +49,9 @@ else()
   set(with_zlib_default OFF)
 endif()
 option(WITH_ZLIB "With ZLIB" ${with_zlib_default})
+if(WITH_ZLIB)
+  list(APPEND BUILT_WITH "ZLIB")
+endif()
 # }
 
 # ZSTD {
@@ -46,6 +66,9 @@ else ()
   endif()
 endif()
 option(WITH_ZSTD "With ZSTD" ${with_zstd_default})
+if(WITH_ZSTD)
+  list(APPEND BUILT_WITH "ZSTD")
+endif()
 # }
 
 # LibDL {
@@ -55,6 +78,9 @@ try_compile(
     "${TRYCOMPILE_SRC_DIR}/dlopen_test.c"
     LINK_LIBRARIES "${CMAKE_DL_LIBS}"
 )
+if(WITH_LIBDL)
+  list(APPEND BUILT_WITH "LIBDL")
+endif()
 # }
 
 # WITH_PLUGINS {
@@ -64,6 +90,9 @@ else()
   set(with_plugins_default OFF)
 endif()
 option(WITH_PLUGINS "With plugin support" ${with_plugins_default})
+if(WITH_PLUGINS)
+  list(APPEND BUILT_WITH "PLUGINS")
+endif()
 # }
 
 # OpenSSL {
@@ -78,38 +107,44 @@ else()
   endif()
 endif()
 option(WITH_SSL "With SSL" ${with_ssl_default})
+if(WITH_SSL)
+  list(APPEND BUILT_WITH "SSL")
+endif()
 # }
 
 # SASL {
 if(WIN32)
   set(with_sasl_default ON)
 else()
-  include(FindPkgConfig)
-  pkg_check_modules(SASL libsasl2)
-  if(SASL_FOUND)
-    set(with_sasl_default ON)
-  else()
-    try_compile(
-        WITH_SASL_CYRUS_BOOL
-        "${CMAKE_CURRENT_BINARY_DIR}/try_compile"
-        "${TRYCOMPILE_SRC_DIR}/libsasl2_test.c"
-        LINK_LIBRARIES "-lsasl2"
-        )
-     if(WITH_SASL_CYRUS_BOOL)
+  if(PkgConfig_FOUND)
+    pkg_check_modules(SASL libsasl2)
+    if(SASL_FOUND)
+      set(with_sasl_default ON)
+    else()
+      try_compile(
+          WITH_SASL_CYRUS_BOOL
+          "${CMAKE_CURRENT_BINARY_DIR}/try_compile"
+          "${TRYCOMPILE_SRC_DIR}/libsasl2_test.c"
+          LINK_LIBRARIES "-lsasl2"
+      )
+      if(WITH_SASL_CYRUS_BOOL)
         set(with_sasl_default ON)
         set(SASL_LIBRARIES "-lsasl2")
-     else()
+      else()
         set(with_sasl_default OFF)
-     endif()
+      endif()
+    endif()
   endif()
 endif()
 option(WITH_SASL "With SASL" ${with_sasl_default})
 if(WITH_SASL)
   if(WITH_SSL)
     set(WITH_SASL_SCRAM ON)
+    list(APPEND BUILT_WITH "SASL_SCRAM")
   endif()
   if(NOT WIN32)
     set(WITH_SASL_CYRUS ON)
+    list(APPEND BUILT_WITH "SASL_CYRUS")
   endif()
 endif()
 # }
@@ -121,14 +156,13 @@ if(ENABLE_LZ4_EXT)
   find_package(LZ4)
   if(LZ4_FOUND)
     set(WITH_LZ4_EXT ON)
+    list(APPEND BUILT_WITH "LZ4_EXT")
   else()
     message(STATUS "Using bundled LZ4 implementation.")
   endif()
 endif()
 # }
 
-# }
-
 option(RDKAFKA_BUILD_STATIC "Build static rdkafka library" OFF)
 option(RDKAFKA_BUILD_EXAMPLES "Build examples" ON)
 option(RDKAFKA_BUILD_TESTS "Build tests" ON)
@@ -146,8 +180,15 @@ endif(WIN32)
 # * HAVE_REGEX
 # * HAVE_STRNDUP
 # * WITH_C11THREADS
+# * WITH_CRC32C_HW
 # * LINK_ATOMIC
 include("packaging/cmake/try_compile/rdkafka_setup.cmake")
+if(WITH_C11THREADS)
+  list(APPEND BUILT_WITH "C11THREADS")
+endif()
+if(WITH_CRC32C_HW)
+  list(APPEND BUILT_WITH "CRC32C_HW")
+endif()
 
 set(GENERATED_DIR "${CMAKE_CURRENT_BINARY_DIR}/generated")
 
@@ -165,6 +206,9 @@ set(GENERATED_DIR "${CMAKE_CURRENT_BINARY_DIR}/generated")
 # * WITH_SASL
 # * HAVE_REGEX
 # * HAVE_STRNDUP
+list(APPEND BUILT_WITH "SNAPPY")
+list(APPEND BUILT_WITH "SOCKEM")
+string(REPLACE ";" " " BUILT_WITH "${BUILT_WITH}")
 configure_file("packaging/cmake/config.h.in" "${GENERATED_DIR}/config.h")
 
 # Installation (https://github.com/forexample/package-example) {

packaging/cmake/config.h.in

@@ -25,6 +25,7 @@
 # endif
 #endif
 
+#cmakedefine01 WITH_PKGCONFIG
 #cmakedefine01 WITH_HDRHISTOGRAM
 #cmakedefine01 WITH_ZLIB
 #cmakedefine01 WITH_ZSTD
@@ -42,3 +43,4 @@
 #cmakedefine01 WITH_C11THREADS
 #cmakedefine01 WITH_CRC32C_HW
 #define SOLIB_EXT "${CMAKE_SHARED_LIBRARY_SUFFIX}"
+#define BUILT_WITH  "${BUILT_WITH}"