From fb7bbf64a2f3b014834cf9bd3b712793d031572b Mon Sep 17 00:00:00 2001
From: Albrecht Schlosser <albrechts.fltk@online.de>
Date: Sat, 27 Jun 2026 17:37:10 +0200
Subject: [PATCH] CMake: improve CMake configuration summary

- reorder parts of the output for clarity
- add C and C++ compilers
- add MinGW environment (env. variable MSYSTEM)
- list all non-empty linker flags (e.g. '-static-libgcc')
---
 CMakeLists.txt | 46 ++++++++++++++++++++++++++++++++++++----------
 1 file changed, 36 insertions(+), 10 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 347324563..eff6e51c5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -412,13 +412,6 @@ message(STATUS "")
 fl_summary("FLTK Library (API) version"   "${FLTK_VERSION}")
 fl_summary("ABI version (FL_ABI_VERSION)" "${FL_ABI_VERSION}")
 
-if(CMAKE_BUILD_TYPE STREQUAL "")
-  fl_summary("Build configuration"        "<unspecified>")
-else()
-  fl_summary("Build configuration"        "${CMAKE_BUILD_TYPE}")
-endif()
-fl_summary("Installation prefix"          "${CMAKE_INSTALL_PREFIX}")
-
 message("")
 #                "title"             name  system library if used
 fl_summary_image("Bundled Libraries" JPEG  LIB_jpeg)
@@ -466,11 +459,44 @@ else()
   fl_summary("${title}" "No")
 endif()
 
+message("")
+message(STATUS "Build Environment:")
 message("")
 
-fl_summary(   "CMAKE_CXX_STANDARD"          "${CMAKE_CXX_STANDARD}")
-fl_summary_yn("CMAKE_CXX_STANDARD_REQUIRED" CMAKE_CXX_STANDARD_REQUIRED)
-fl_summary_yn("CMAKE_CXX_EXTENSIONS"        CMAKE_CXX_EXTENSIONS)
+if(CMAKE_BUILD_TYPE STREQUAL "")
+  fl_summary("Build configuration"            "<unspecified>")
+else()
+  fl_summary("Build configuration"            "${CMAKE_BUILD_TYPE}")
+endif()
+fl_summary("Installation prefix"              "${CMAKE_INSTALL_PREFIX}")
+if(MINGW)
+  fl_summary("MinGW Environment (MSYSTEM)"    "$ENV{MSYSTEM}")
+endif()
+fl_summary("C Compiler"                       "${CMAKE_C_COMPILER}")
+fl_summary("C++ Compiler"                     "${CMAKE_CXX_COMPILER}")
+fl_summary(   "CMAKE_CXX_STANDARD"            "${CMAKE_CXX_STANDARD}")
+fl_summary_yn("CMAKE_CXX_STANDARD_REQUIRED"   CMAKE_CXX_STANDARD_REQUIRED)
+fl_summary_yn("CMAKE_CXX_EXTENSIONS"          CMAKE_CXX_EXTENSIONS)
+
+# Optional linker flags: only non-empty flags are listed
+
+message("")
+foreach(_build_type "" "_DEBUG" "_RELEASE")
+  foreach(_link_type "EXE" "MODULE" "SHARED" "STATIC")
+    set(_var "CMAKE_${_link_type}_LINKER_FLAGS${_build_type}")
+    set(_flags ${${_var}})
+    if(NOT "${_flags}" STREQUAL "")
+      # The *1st* line outputs the information in table format.
+      # The *2nd* line outputs it properly formatted for cut'n'paste to the commandline for testing.
+      set(_table FALSE)
+      if(_table)
+        fl_summary("${_var}" "'${_flags}'")
+      else()
+        message(STATUS "${_var}='${_flags}'")
+      endif()
+    endif()
+  endforeach()
+endforeach()
 
 message("")
 message(STATUS "End of Configuration Summary --\n")