Merge branch 'build_cmake' of https://github.com/TcT2k/wxWidgets

Add CMake-based build system.

Merge the original branch without any changes except for resolving the
conflict due to moving the contents of .travis.yml to a separate file by
propagating the changes done in this file since then to the new script
and rerunning ./build/update-setup-h and ./build/cmake/update_files.py
to update the file lists changed in the meanwhile.

Closes https://github.com/wxWidgets/wxWidgets/pull/330

build/cmake/main.cmake

@@ -0,0 +1,75 @@
+#############################################################################
+# Name:        build/cmake/main.cmake
+# Purpose:     Main CMake file
+# Author:      Tobias Taschner
+# Created:     2016-09-20
+# Copyright:   (c) 2016 wxWidgets development team
+# Licence:     wxWindows licence
+#############################################################################
+
+list(APPEND CMAKE_MODULE_PATH "${wxSOURCE_DIR}/build/cmake/modules")
+
+include(build/cmake/files.cmake)            # Files list
+include(build/cmake/functions.cmake)        # wxWidgets functions
+include(build/cmake/toolkit.cmake)          # Platform/toolkit settings
+include(build/cmake/options.cmake)          # User options
+include(build/cmake/init.cmake)             # Init various global build vars
+include(build/cmake/install.cmake)          # Install target support
+
+add_subdirectory(build/cmake/lib libs)
+add_subdirectory(build/cmake/utils utils)
+
+if(wxBUILD_SAMPLES)
+    add_subdirectory(build/cmake/samples samples)
+endif()
+
+if(wxBUILD_TESTS)
+    enable_testing()
+    add_subdirectory(build/cmake/tests tests)
+endif()
+
+if(wxBUILD_DEMOS)
+    add_subdirectory(build/cmake/demos demos)
+endif()
+
+if(NOT wxBUILD_CUSTOM_SETUP_HEADER_PATH)
+    # Write setup.h after all variables are available
+    include(build/cmake/setup.cmake)
+endif()
+
+if(UNIX)
+    # Write wx-config
+    include(build/cmake/config.cmake)
+endif()
+
+# Determine minimum required OS at runtime
+set(wxREQUIRED_OS_DESC "${CMAKE_SYSTEM_NAME} ${CMAKE_SYSTEM_PROCESSOR}")
+if(MSVC OR MINGW OR CYGWIN)
+    # Determine based on used toolkit
+    if(MINGW OR CYGWIN OR (MSVC_VERSION LESS 1700) OR (CMAKE_VS_PLATFORM_TOOLSET MATCHES "_xp$") )
+        # Visual Studio < 2012 and MinGW always create XP compatible binaries
+        # XP Toolset is required since VS 2012
+        set(wxREQUIRED_OS_DESC "Windows XP / Windows Server 2003")
+    else()
+        set(wxREQUIRED_OS_DESC "Windows Vista / Windows Server 2008")
+    endif()
+    if(CMAKE_CL_64)
+        wx_string_append(wxREQUIRED_OS_DESC " (x64 Edition)")
+    endif()
+elseif(APPLE AND NOT IPHONE)
+    if(DEFINED CMAKE_OSX_DEPLOYMENT_TARGET)
+        set(wxREQUIRED_OS_DESC "macOS ${CMAKE_OSX_DEPLOYMENT_TARGET}")
+    endif()
+endif()
+
+# Print configuration summary
+wx_print_thirdparty_library_summary()
+
+message(STATUS "Configured wxWidgets ${wxVERSION} for ${CMAKE_SYSTEM}
+    Min OS Version required at runtime:                ${wxREQUIRED_OS_DESC}
+    Which GUI toolkit should wxWidgets use?:           ${wxBUILD_TOOLKIT} ${wxTOOLKIT_VERSION}
+    Should wxWidgets be compiled into single library?  ${wxBUILD_MONOLITHIC}
+    Should wxWidgets be linked as a shared library?    ${wxBUILD_SHARED}
+    Should wxWidgets support Unicode?                  ${wxUSE_UNICODE}
+    What level of wxWidgets compatibility should be enabled? ${wxBUILD_COMPATIBILITY}"
+    )