CMake: refactor inclusion of external libraries.

This commit makes common external packages always be included through
find_package to eliminate differences in variables set, wraps
find_package for vendored libraries on Windows to factor out common
code, and removes miscellaneous useless code elsewhere in dependency
handling.

This also fixes a problem where pkg-config would pick up `build`
libraries instead of `host` when cross-compiling.

.gitmodules

@@ -5,8 +5,8 @@
 [submodule "extlib/libpng"]
 	path = extlib/libpng
 	url = https://github.com/glennrp/libpng
-[submodule "extlib/libfreetype"]
+[submodule "extlib/freetype"]
-	path = extlib/libfreetype
+	path = extlib/freetype
 	url = http://git.sv.nongnu.org/r/freetype/freetype2.git
 [submodule "extlib/libdxfrw"]
 	path = extlib/libdxfrw

CMakeLists.txt

@@ -121,56 +121,26 @@ message(STATUS "Using in-tree libdxfrw")
 add_subdirectory(extlib/libdxfrw)
 
 if(WIN32)
-    # Configure Freetype first. If done later, it will notice that
+    include(FindVendoredPackage)
-    # zlib is available, try to use it and promptly break on MSVC
-    # in a very obscure way. Given that the only use of zlib, bzip2
-    # and png support is in support for extremely obsolete Unix fonts,
-    # we don't care.
-    find_package(Freetype)
 
-    if(NOT FREETYPE_FOUND)
+    find_vendored_package(Freetype freetype
-        message(STATUS "Using in-tree libfreetype")
+        WITH_ZLIB               OFF
+        WITH_BZip2              OFF
+        WITH_PNG                OFF
+        WITH_HarfBuzz           OFF
+        FREETYPE_LIBRARY        freetype
+        FREETYPE_INCLUDE_DIRS   ${CMAKE_SOURCE_DIR}/extlib/freetype/include)
 
-        add_subdirectory(extlib/libfreetype EXCLUDE_FROM_ALL)
+    find_vendored_package(ZLIB zlib
+        ZLIB_LIBRARY            zlibstatic
+        ZLIB_INCLUDE_DIR        ${CMAKE_SOURCE_DIR}/extlib/zlib)
+    list(APPEND ZLIB_INCLUDE_DIR ${CMAKE_BINARY_DIR}/extlib/zlib)
 
-        set(FREETYPE_LIBRARY
+    find_vendored_package(PNG libpng
-            freetype)
+        SKIP_INSTALL_ALL        ON
-        set(FREETYPE_INCLUDE_DIRS
+        PNG_LIBRARY             png16_static
-            "${CMAKE_SOURCE_DIR}/extlib/libfreetype/include")
+        PNG_PNG_INCLUDE_DIR     ${CMAKE_SOURCE_DIR}/extlib/libpng)
-        find_package(Freetype REQUIRED)
+    list(APPEND PNG_PNG_INCLUDE_DIR ${CMAKE_BINARY_DIR}/extlib/libpng)
-    endif()
-
-    find_package(ZLIB)
-
-    if(NOT ZLIB_FOUND)
-        message(STATUS "Using in-tree zlib")
-        add_subdirectory(extlib/zlib EXCLUDE_FROM_ALL)
-
-        message(STATUS "Using in-tree libpng")
-        set(ZLIB_LIBRARY
-            zlibstatic)
-        set(ZLIB_INCLUDE_DIR
-            "${CMAKE_SOURCE_DIR}/extlib/zlib"
-            "${CMAKE_BINARY_DIR}/extlib/zlib")
-        find_package(ZLIB REQUIRED)
-    endif()
-
-    find_package(PNG)
-
-    if(NOT PNG_FOUND)
-        message(STATUS "Using in-tree libpng")
-
-        set(SKIP_INSTALL_ALL
-            ON)
-        add_subdirectory(extlib/libpng EXCLUDE_FROM_ALL)
-
-        set(PNG_LIBRARY
-            png16_static)
-        set(PNG_PNG_INCLUDE_DIR
-            "${CMAKE_SOURCE_DIR}/extlib/libpng"
-            "${CMAKE_BINARY_DIR}/extlib/libpng")
-        find_package(PNG REQUIRED)
-    endif()
 
     if(NOT MINGW)
         message(STATUS "Using prebuilt SpaceWare")
@@ -183,20 +153,25 @@ if(WIN32)
 elseif(APPLE)
     set(CMAKE_FIND_FRAMEWORK LAST)
 
+    find_package(ZLIB REQUIRED)
     find_package(PNG REQUIRED)
     find_package(Freetype REQUIRED)
+
     find_library(APPKIT_LIBRARY AppKit REQUIRED)
 else() # Linux and compatible systems
     find_package(Backtrace)
     find_package(SpaceWare)
 
-    # Use freedesktop's pkg-config to locate everything.
+    find_package(ZLIB REQUIRED)
+    find_package(PNG REQUIRED)
+    find_package(Freetype REQUIRED)
+
+    # Use freedesktop's pkg-config to locate everything else.
     find_package(PkgConfig REQUIRED)
-    pkg_check_modules(ZLIB REQUIRED zlib)
-    pkg_check_modules(PNG REQUIRED libpng)
     pkg_check_modules(FONTCONFIG REQUIRED fontconfig)
     pkg_check_modules(JSONC REQUIRED json-c)
     pkg_check_modules(FREETYPE REQUIRED freetype2)
+    pkg_check_modules(CAIRO REQUIRED cairo)
 
     set(HAVE_GTK TRUE)
     if(GUI STREQUAL "gtk3")

cmake/DisableWarnings.cmake

@@ -0,0 +1,15 @@
+# Disables all warnings on MSVC and GNU-compatible compilers.
+
+function(disable_warnings)
+    if(CMAKE_C_COMPILER_ID STREQUAL GNU OR CMAKE_C_COMPILER_ID STREQUAL Clang)
+        set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -w" PARENT_SCOPE)
+    elseif(CMAKE_C_COMPILER_ID STREQUAL MSVC)
+        set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /W0" PARENT_SCOPE)
+    endif()
+
+    if(CMAKE_CXX_COMPILER_ID STREQUAL GNU OR CMAKE_CXX_COMPILER_ID STREQUAL Clang)
+        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -w" PARENT_SCOPE)
+    elseif(CMAKE_CXX_COMPILER_ID STREQUAL MSVC)
+        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W0" PARENT_SCOPE)
+    endif()
+endfunction()

cmake/FindVendoredPackage.cmake

@@ -0,0 +1,54 @@
+# Find the given library in the system locations, or build in-tree if not found.
+#
+# Arguments:
+#   PKG_NAME - name of the package as passed to find_package
+#   PKG_PATH - name of the source tree relative to extlib/
+#
+# The rest of the arguments are VARIABLE VALUE pairs. If the library is not found,
+# every VARIABLE will be set to VALUE and find_package will be rerun with the REQUIRED flag.
+# Regardless of where the library was found, only the specfied VARIABLEs that start with
+# ${PKG_NAME} will be set in the parent scope.
+#
+# All warnings in the in-tree package are disabled.
+
+include(DisableWarnings)
+
+function(find_vendored_package PKG_NAME PKG_PATH)
+    find_package(${PKG_NAME})
+
+    set(cfg_name)
+    foreach(item ${ARGN})
+        if(NOT cfg_name)
+            set(cfg_name ${item})
+        else()
+            set(${cfg_name} ${item})
+            set(cfg_name)
+        endif()
+    endforeach()
+
+    disable_warnings()
+
+    string(TOUPPER ${PKG_NAME} VAR_NAME)
+    if(NOT ${VAR_NAME}_FOUND)
+        message(STATUS "Using in-tree ${PKG_PATH}")
+        set(${VAR_NAME}_IN_TREE YES CACHE INTERNAL "")
+
+        add_subdirectory(extlib/${PKG_PATH} EXCLUDE_FROM_ALL)
+        find_package(${PKG_NAME} REQUIRED)
+    elseif(${VAR_NAME}_IN_TREE)
+        add_subdirectory(extlib/${PKG_PATH} EXCLUDE_FROM_ALL)
+    endif()
+
+    # Now put everything we just discovered into the cache.
+    set(cfg_name)
+    foreach(item ${ARGN} ${VAR_NAME}_FOUND)
+        if(NOT cfg_name)
+            set(cfg_name ${item})
+        else()
+            if(cfg_name MATCHES "^${VAR_NAME}")
+                set(${cfg_name} "${${cfg_name}}" CACHE INTERNAL "")
+            endif()
+            set(cfg_name)
+        endif()
+    endforeach()
+endfunction()

cmake/Toolchain-mingw32.cmake

@@ -1,13 +1,15 @@
-SET(CMAKE_SYSTEM_NAME Windows)
+set(CMAKE_SYSTEM_NAME Windows)
 
-SET(TRIPLE i686-w64-mingw32)
+set(TRIPLE i686-w64-mingw32)
 
-SET(CMAKE_C_COMPILER ${TRIPLE}-gcc)
+set(CMAKE_C_COMPILER ${TRIPLE}-gcc)
-SET(CMAKE_CXX_COMPILER ${TRIPLE}-g++)
+set(CMAKE_CXX_COMPILER ${TRIPLE}-g++)
-SET(CMAKE_RC_COMPILER ${TRIPLE}-windres)
+set(CMAKE_RC_COMPILER ${TRIPLE}-windres)
 
-SET(CMAKE_FIND_ROOT_PATH /usr/${TRIPLE})
+set(CMAKE_FIND_ROOT_PATH /usr/${TRIPLE})
 
 set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
 set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
 set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+
+set(ENV{PKG_CONFIG_LIBDIR} /usr/${TRIPLE}/lib/pkgconfig)

cmake/Toolchain-mingw64.cmake

@@ -1,13 +1,15 @@
-SET(CMAKE_SYSTEM_NAME Windows)
+set(CMAKE_SYSTEM_NAME Windows)
 
-SET(TRIPLE x86_64-w64-mingw32)
+set(TRIPLE x86_64-w64-mingw32)
 
-SET(CMAKE_C_COMPILER ${TRIPLE}-gcc)
+set(CMAKE_C_COMPILER ${TRIPLE}-gcc)
-SET(CMAKE_CXX_COMPILER ${TRIPLE}-g++)
+set(CMAKE_CXX_COMPILER ${TRIPLE}-g++)
-SET(CMAKE_RC_COMPILER ${TRIPLE}-windres)
+set(CMAKE_RC_COMPILER ${TRIPLE}-windres)
 
-SET(CMAKE_FIND_ROOT_PATH /usr/${TRIPLE})
+set(CMAKE_FIND_ROOT_PATH /usr/${TRIPLE})
 
 set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
 set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
 set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+
+set(ENV{PKG_CONFIG_LIBDIR} /usr/${TRIPLE}/lib/pkgconfig)

src/CMakeLists.txt

@@ -1,31 +1,12 @@
-# global
-
 include(GNUInstallDirs)
 
-include_directories(
+# configuration
-    ${OPENGL_INCLUDE_DIR}
-    ${PNG_INCLUDE_DIRS}
-    ${FREETYPE_INCLUDE_DIRS})
-
-link_directories(
-    ${PNG_LIBRARY_DIRS}
-    ${FREETYPE_LIBRARY_DIRS})
-
-add_definitions(
-    ${PNG_CFLAGS_OTHER})
 
 include_directories(
     ${CMAKE_CURRENT_SOURCE_DIR}
-    ${CMAKE_CURRENT_SOURCE_DIR}/built
     ${CMAKE_CURRENT_BINARY_DIR})
 
-if(SPACEWARE_FOUND)
-    include_directories(
-        ${SPACEWARE_INCLUDE_DIR})
-endif()
-
 set(HAVE_SPACEWARE ${SPACEWARE_FOUND})
-set(HAVE_GTK ${GTKMM_FOUND})
 configure_file(${CMAKE_CURRENT_SOURCE_DIR}/config.h.in
                ${CMAKE_CURRENT_BINARY_DIR}/config.h)
 
@@ -75,16 +56,28 @@ if(NOT WIN32)
         PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
 endif()
 
-# platform dependencies
+# solvespace dependencies
+
+include_directories(
+    ${OPENGL_INCLUDE_DIR}
+    ${ZLIB_INCLUDE_DIR}
+    ${PNG_PNG_INCLUDE_DIR}
+    ${FREETYPE_INCLUDE_DIRS})
+
+if(SPACEWARE_FOUND)
+    include_directories(
+        ${SPACEWARE_INCLUDE_DIR})
+endif()
 
 if(WIN32)
     set(platform_SOURCES
         platform/w32main.cpp)
 
     set(platform_LIBRARIES
-        comctl32)
+        comctl32
+        ${SPACEWARE_LIBRARIES})
 elseif(APPLE)
-    add_definitions(
+    add_compile_options(
         -fobjc-arc)
 
     set(platform_SOURCES
@@ -98,29 +91,19 @@ elseif(APPLE)
     set(platform_LIBRARIES
         ${APPKIT_LIBRARY})
 elseif(HAVE_GTK)
-    include_directories(
-        ${GTKMM_INCLUDE_DIRS}
-        ${JSONC_INCLUDE_DIRS}
-        ${FONTCONFIG_INCLUDE_DIRS})
-
-    link_directories(
-        ${GTKMM_LIBRARY_DIRS}
-        ${JSONC_LIBRARY_DIRS}
-        ${FONTCONFIG_LIBRARY_DIRS})
-
-    add_definitions(
-        ${GTKMM_CFLAGS_OTHER}
-        ${JSONC_CFLAGS_OTHER}
-        ${FONTCONFIG_CFLAGS_OTHER})
-
     set(platform_SOURCES
         platform/gtkmain.cpp
         render/rendergl.cpp)
 
     set(platform_LIBRARIES
-        ${GTKMM_LIBRARIES}
+        ${Backtrace_LIBRARIES}
-        ${JSONC_LIBRARIES}
+        ${SPACEWARE_LIBRARIES})
-        ${FONTCONFIG_LIBRARIES})
+
+    foreach(pkg_config_lib GTKMM JSONC FONTCONFIG)
+        include_directories(${${pkg_config_lib}_INCLUDE_DIRS})
+        link_directories(${${pkg_config_lib}_LIBRARY_DIRS})
+        list(APPEND platform_LIBRARIES ${${pkg_config_lib}_LIBRARIES})
+    endforeach()
 endif()
 
 # solvespace executable
@@ -199,9 +182,9 @@ add_dependencies(solvespace
 target_link_libraries(solvespace
     dxfrw
     ${OPENGL_LIBRARIES}
-    ${PNG_LIBRARIES}
+    ${ZLIB_LIBRARY}
-    ${ZLIB_LIBRARIES}
+    ${PNG_LIBRARY}
-    ${FREETYPE_LIBRARIES}
+    ${FREETYPE_LIBRARY}
     ${platform_LIBRARIES})
 
 if(WIN32 AND NOT MINGW)
@@ -209,16 +192,6 @@ if(WIN32 AND NOT MINGW)
         LINK_FLAGS "/MANIFEST:NO /SAFESEH:NO")
 endif()
 
-if(SPACEWARE_FOUND)
-    target_link_libraries(solvespace
-        ${SPACEWARE_LIBRARIES})
-endif()
-
-if(Backtrace_FOUND)
-    target_link_libraries(solvespace
-        ${Backtrace_LIBRARIES})
-endif()
-
 if(APPLE)
     foreach(lib ${platform_BUNDLED_LIBS})
         get_filename_component(name ${lib} NAME)