commit 343fa8f0cbad19402a2533651acc53149be1fcf5
Author: Didier Raboud <odyx@debian.org>
Date:   Wed Nov 27 18:53:28 2013 +0100

    Add a PLATFORM_GNU global variable matching all GNU systems such as Debian's Linux, kFreeBSD and Hurd

diff --git a/CMakeLists.txt b/CMakeLists.txt
index ff30513..c4c3e39 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -42,6 +42,7 @@ message(STATUS "Building Colobot \"${COLOBOT_VERSION_CODENAME}\" (${COLOBOT_VERS
 if("${CMAKE_SYSTEM_NAME}" MATCHES "Windows")
     message(STATUS "Build for Windows system")
     set(PLATFORM_WINDOWS 1)
+    set(PLATFORM_GNU     0)
     set(PLATFORM_LINUX   0)
     set(PLATFORM_MACOSX  0)
     set(PLATFORM_OTHER   0)
@@ -52,15 +53,27 @@ elseif("${CMAKE_SYSTEM_NAME}" MATCHES "Linux")
     message(STATUS "Build for Linux system")
     set(PLATFORM_WINDOWS 0)
     set(PLATFORM_LINUX   1)
+    set(PLATFORM_GNU     1)
     set(PLATFORM_MACOSX  0)
     set(PLATFORM_OTHER   0)
 
     # Platform-dependent implementation of system.h
     set(SYSTEM_CPP_MODULE "system_linux.cpp")
+elseif("${CMAKE_SYSTEM_NAME}" MATCHES "kFreeBSD" OR "${CMAKE_SYSTEM_NAME}" STREQUAL "GNU")
+    message(STATUS "Build for kFreeBSD system")
+    set(PLATFORM_WINDOWS 0)
+    set(PLATFORM_LINUX   0)
+    set(PLATFORM_GNU     1)
+    set(PLATFORM_MACOSX  0)
+    set(PLATFORM_OTHER   0)
+
+    # Platform-dependent implementation of system.h
+    set(SYSTEM_CPP_MODULE "system_other.cpp")
 elseif("${CMAKE_SYSTEM_NAME}" MATCHES "Darwin")
     message(STATUS "Build for Mac OSX system")
     set(PLATFORM_WINDOWS 0)
     set(PLATFORM_LINUX   0)
+    set(PLATFORM_GNU     0)
     set(PLATFORM_MACOSX  1)
     set(PLATFORM_OTHER   0)
     
@@ -72,6 +85,7 @@ else()
     message(STATUS "Build for other system")
     set(PLATFORM_WINDOWS 0)
     set(PLATFORM_LINUX   0)
+    set(PLATFORM_GNU     0)
     set(PLATFORM_MACOSX  0)
     set(PLATFORM_OTHER   1)
 
@@ -226,7 +240,7 @@ include("${colobot_SOURCE_DIR}/cmake/msys.cmake")
 ##
 # Clipboard support needs X11 libraries
 ##
-if(PLATFORM_LINUX OR PLATFORM_MACOSX)
+if(PLATFORM_GNU OR PLATFORM_MACOSX)
     find_package(X11 REQUIRED)
     if(PLATFORM_MACOSX)
        # Add the includes for X11
diff --git a/desktop/CMakeLists.txt b/desktop/CMakeLists.txt
index 9fa0c5e..87c8a4b 100644
--- a/desktop/CMakeLists.txt
+++ b/desktop/CMakeLists.txt
@@ -4,7 +4,7 @@ set(COLOBOT_ICON_FILE colobot.svg)
 
 # Render SVG icon in various sizes
 find_program(RSVG_CONVERT rsvg-convert)
-if(RSVG_CONVERT AND (PLATFORM_LINUX OR PLATFORM_MACOSX))
+if(RSVG_CONVERT AND (PLATFORM_GNU OR PLATFORM_MACOSX))
     add_custom_target(png-icons ALL)
     foreach(PNGSIZE 512 256 128 48 32 16)
         add_custom_command(
@@ -15,7 +15,7 @@ if(RSVG_CONVERT AND (PLATFORM_LINUX OR PLATFORM_MACOSX))
         add_custom_target(png-icon-${PNGSIZE} ALL DEPENDS ${PNGSIZE}/colobot.png)
         add_dependencies(png-icons png-icon-${PNGSIZE})
 
-        if(PLATFORM_LINUX)
+        if(PLATFORM_GNU)
             install(
                 FILES ${CMAKE_CURRENT_BINARY_DIR}/${PNGSIZE}/colobot.png
                 DESTINATION ${CMAKE_INSTALL_PREFIX}/share/icons/hicolor/${PNGSIZE}x${PNGSIZE}/apps/
@@ -37,7 +37,7 @@ if(RSVG_CONVERT AND (PLATFORM_LINUX OR PLATFORM_MACOSX))
 
 endif()
 
-if(PLATFORM_LINUX)
+if(PLATFORM_GNU)
     # Install Desktop Entry file
     set(COLOBOT_DESKTOP_FILE colobot.desktop)
     add_custom_command(
@@ -112,7 +112,7 @@ if(PLATFORM_LINUX)
             endforeach()
         endif()
     endif()
-endif(PLATFORM_LINUX)
+endif(PLATFORM_GNU)
 
 if(PLATFORM_MACOSX)
     configure_file(Info.plist.cmake ${CMAKE_CURRENT_BINARY_DIR}/Info.plist)
diff --git a/lib/clipboard/CMakeLists.txt b/lib/clipboard/CMakeLists.txt
index a189ec4..7999cc1 100644
--- a/lib/clipboard/CMakeLists.txt
+++ b/lib/clipboard/CMakeLists.txt
@@ -7,8 +7,6 @@ add_definitions(-DLIB_COMPILE=1)
 
 if(PLATFORM_WINDOWS)
     set(CLIPBOARD_SRC src/clipboardWin32.c)
-elseif(PLATFORM_LINUX)
-    set(CLIPBOARD_SRC src/clipboardX11.c)
 else()
     set(CLIPBOARD_SRC src/clipboardX11.c)
 endif()
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index ef59973..c32f054 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -28,6 +28,8 @@ if(MXE) # MXE requires special treatment
 elseif(PLATFORM_WINDOWS)
     # because it isn't included in standard linking libraries
     set(PLATFORM_LIBS "-lintl")
+elseif(PLATFORM_GNU)
+    set(PLATFORM_LIBS "-lX11")
 elseif(PLATFORM_LINUX)
     # for clock_gettime
     set(PLATFORM_LIBS "-lrt -lX11")
diff --git a/src/common/config.h.cmake b/src/common/config.h.cmake
index 63cd93b..6408b6e 100644
--- a/src/common/config.h.cmake
+++ b/src/common/config.h.cmake
@@ -3,6 +3,7 @@
 // Macros set by CMake
 #cmakedefine PLATFORM_WINDOWS @PLATFORM_WINDOWS@
 #cmakedefine PLATFORM_LINUX @PLATFORM_LINUX@
+#cmakedefine PLATFORM_GNU @PLATFORM_GNU@
 #cmakedefine PLATFORM_MACOSX @PLATFORM_MACOSX@
 #cmakedefine PLATFORM_OTHER @PLATFORM_OTHER@
 
diff --git a/test/unit/CMakeLists.txt b/test/unit/CMakeLists.txt
index 38bffda..278519f 100644
--- a/test/unit/CMakeLists.txt
+++ b/test/unit/CMakeLists.txt
@@ -6,6 +6,8 @@ if(MXE) # MXE requires special treatment
 elseif(PLATFORM_WINDOWS)
     # because it isn't included in standard linking libraries
     set(PLATFORM_LIBS "-lintl")
+elseif(PLATFORM_GNU)
+    set(PLATFORM_LIBS "-lX11")
 elseif(PLATFORM_LINUX)
     # for clock_gettime
     set(PLATFORM_LIBS "-lrt -lX11")
diff --git a/test/unit/ui/CMakeLists.txt b/test/unit/ui/CMakeLists.txt
index 8086967..503f84b 100644
--- a/test/unit/ui/CMakeLists.txt
+++ b/test/unit/ui/CMakeLists.txt
@@ -10,8 +10,6 @@ ${CLIPBOARD_INCLUDE_DIR}
 
 # Platform-dependent implementation of CSystemUtils
 if(PLATFORM_WINDOWS)
-elseif(PLATFORM_LINUX)
-    set(ADDITIONAL_LIB "-lX11")
 elseif(PLATFORM_MACOSX)
     set(ADDITIONAL_LIB "${X11_X11_LIB}")
 else()