Detect incompatible libtorrent v2 versions in build systems

Although the detection is working, the error message in autotools is not perfect, i.e. it would only mention valid range for libtorrent v1 and it shouldn't be a problem since v2 support isn't fully ready yet.
3 years ago · 7d7f967d5e
5 changed files with 236 additions and 63 deletions
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@ -14,7 +14,8 @@ set(CMAKE_FIND_PACKAGE_PREFER_CONFIG ON)
				@@ -14,7 +14,8 @@ set(CMAKE_FIND_PACKAGE_PREFER_CONFIG ON)
 set(minBoostVersion 1.65)
 set(minQtVersion 5.15.2)
 set(minOpenSSLVersion 1.1.1)
-set(minLibtorrentVersion 1.2.14)
+set(minLibtorrent1Version 1.2.14)
+set(minLibtorrentVersion 2.0.4)
 set(minZlibVersion 1.2.11)

 # features (some are platform-specific)
--- a/12
+++ b/12
@ -5,8 +5,8 @@ qBittorrent - A BitTorrent client in C++ / Qt
				@@ -5,8 +5,8 @@ qBittorrent - A BitTorrent client in C++ / Qt

  - Boost >= 1.65

-  - libtorrent-rasterbar >= 1.2.14 (by Arvid Norberg)
-      * https://www.libtorrent.org/
+  - libtorrent-rasterbar: (>= 1.2.14) || (>= 2.0.4)
+      * By Arvid Norberg, https://www.libtorrent.org/
      * Be careful: another library (the one used by rTorrent) uses a similar name

  - OpenSSL >= 1.1.1
@ -15,10 +15,12 @@ qBittorrent - A BitTorrent client in C++ / Qt
				@@ -15,10 +15,12 @@ qBittorrent - A BitTorrent client in C++ / Qt

  - zlib >= 1.2.11

-  - pkg-config (compile-time only on *nix systems)
+  - pkg-config
+      * Compile-time only on *nix systems

-  - Python >= 3.5.0 (optional, runtime only)
-      * Required by the internal search engine
+  - Python >= 3.5.0
+      * Optional, run-time only
+      * Used by the bundled search engine

 Dependency version numbers are bumped every once in a while to keep the range of properly tested configurations manageable, even if not strictly required to build.
 You may be able to build with older versions of (some of) the dependencies other than the minimum versions specified in the build scripts, but support for such builds is not provided - you are on your own.
--- a/198
+++ b/198
@ -5522,8 +5522,8 @@ if test "x$enable_gui" = "xyes"
				@@ -5522,8 +5522,8 @@ if test "x$enable_gui" = "xyes"
 then :

 pkg_failed=no
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for Qt5Svg" >&5
-printf %s "checking for Qt5Svg... " >&6; }
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for Qt5Svg >= 5.15.2" >&5
+printf %s "checking for Qt5Svg >= 5.15.2... " >&6; }

 if test -n "$Qt5Svg_CFLAGS"; then
    pkg_cv_Qt5Svg_CFLAGS="$Qt5Svg_CFLAGS"
@ -6032,19 +6032,19 @@ rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
				@@ -6032,19 +6032,19 @@ rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext


 pkg_failed=no
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for libtorrent" >&5
-printf %s "checking for libtorrent... " >&6; }
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for libtorrent-rasterbar >= 2.0.4" >&5
+printf %s "checking for libtorrent-rasterbar >= 2.0.4... " >&6; }

 if test -n "$libtorrent_CFLAGS"; then
    pkg_cv_libtorrent_CFLAGS="$libtorrent_CFLAGS"
 elif test -n "$PKG_CONFIG"; then
    if test -n "$PKG_CONFIG" && \
-    { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$PKG_CONFIG --exists --print-errors \"libtorrent-rasterbar >= 1.2.14\""; } >&5
-  ($PKG_CONFIG --exists --print-errors "libtorrent-rasterbar >= 1.2.14") 2>&5
+    { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$PKG_CONFIG --exists --print-errors \"libtorrent-rasterbar >= 2.0.4\""; } >&5
+  ($PKG_CONFIG --exists --print-errors "libtorrent-rasterbar >= 2.0.4") 2>&5
  ac_status=$?
  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
  test $ac_status = 0; }; then
-  pkg_cv_libtorrent_CFLAGS=`$PKG_CONFIG --cflags "libtorrent-rasterbar >= 1.2.14" 2>/dev/null`
+  pkg_cv_libtorrent_CFLAGS=`$PKG_CONFIG --cflags "libtorrent-rasterbar >= 2.0.4" 2>/dev/null`
 		      test "x$?" != "x0" && pkg_failed=yes
 else
  pkg_failed=yes
@ -6056,12 +6056,12 @@ if test -n "$libtorrent_LIBS"; then
				@@ -6056,12 +6056,12 @@ if test -n "$libtorrent_LIBS"; then
    pkg_cv_libtorrent_LIBS="$libtorrent_LIBS"
 elif test -n "$PKG_CONFIG"; then
    if test -n "$PKG_CONFIG" && \
-    { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$PKG_CONFIG --exists --print-errors \"libtorrent-rasterbar >= 1.2.14\""; } >&5
-  ($PKG_CONFIG --exists --print-errors "libtorrent-rasterbar >= 1.2.14") 2>&5
+    { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$PKG_CONFIG --exists --print-errors \"libtorrent-rasterbar >= 2.0.4\""; } >&5
+  ($PKG_CONFIG --exists --print-errors "libtorrent-rasterbar >= 2.0.4") 2>&5
  ac_status=$?
  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
  test $ac_status = 0; }; then
-  pkg_cv_libtorrent_LIBS=`$PKG_CONFIG --libs "libtorrent-rasterbar >= 1.2.14" 2>/dev/null`
+  pkg_cv_libtorrent_LIBS=`$PKG_CONFIG --libs "libtorrent-rasterbar >= 2.0.4" 2>/dev/null`
 		      test "x$?" != "x0" && pkg_failed=yes
 else
  pkg_failed=yes
@ -6082,14 +6082,167 @@ else
				@@ -6082,14 +6082,167 @@ else
        _pkg_short_errors_supported=no
 fi
        if test $_pkg_short_errors_supported = yes; then
-	        libtorrent_PKG_ERRORS=`$PKG_CONFIG --short-errors --print-errors --cflags --libs "libtorrent-rasterbar >= 1.2.14" 2>&1`
+	        libtorrent_PKG_ERRORS=`$PKG_CONFIG --short-errors --print-errors --cflags --libs "libtorrent-rasterbar >= 2.0.4" 2>&1`
        else
-	        libtorrent_PKG_ERRORS=`$PKG_CONFIG --print-errors --cflags --libs "libtorrent-rasterbar >= 1.2.14" 2>&1`
+	        libtorrent_PKG_ERRORS=`$PKG_CONFIG --print-errors --cflags --libs "libtorrent-rasterbar >= 2.0.4" 2>&1`
        fi
 	# Put the nasty error message in config.log where it belongs
 	echo "$libtorrent_PKG_ERRORS" >&5

-	as_fn_error $? "Package requirements (libtorrent-rasterbar >= 1.2.14) were not met:
+
+pkg_failed=no
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2" >&5
+printf %s "checking for libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2... " >&6; }
+
+if test -n "$libtorrent_CFLAGS"; then
+    pkg_cv_libtorrent_CFLAGS="$libtorrent_CFLAGS"
+ elif test -n "$PKG_CONFIG"; then
+    if test -n "$PKG_CONFIG" && \
+    { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$PKG_CONFIG --exists --print-errors \"libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2\""; } >&5
+  ($PKG_CONFIG --exists --print-errors "libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2") 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then
+  pkg_cv_libtorrent_CFLAGS=`$PKG_CONFIG --cflags "libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2" 2>/dev/null`
+		      test "x$?" != "x0" && pkg_failed=yes
+else
+  pkg_failed=yes
+fi
+ else
+    pkg_failed=untried
+fi
+if test -n "$libtorrent_LIBS"; then
+    pkg_cv_libtorrent_LIBS="$libtorrent_LIBS"
+ elif test -n "$PKG_CONFIG"; then
+    if test -n "$PKG_CONFIG" && \
+    { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$PKG_CONFIG --exists --print-errors \"libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2\""; } >&5
+  ($PKG_CONFIG --exists --print-errors "libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2") 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then
+  pkg_cv_libtorrent_LIBS=`$PKG_CONFIG --libs "libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2" 2>/dev/null`
+		      test "x$?" != "x0" && pkg_failed=yes
+else
+  pkg_failed=yes
+fi
+ else
+    pkg_failed=untried
+fi
+
+
+
+if test $pkg_failed = yes; then
+        { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+
+if $PKG_CONFIG --atleast-pkgconfig-version 0.20; then
+        _pkg_short_errors_supported=yes
+else
+        _pkg_short_errors_supported=no
+fi
+        if test $_pkg_short_errors_supported = yes; then
+	        libtorrent_PKG_ERRORS=`$PKG_CONFIG --short-errors --print-errors --cflags --libs "libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2" 2>&1`
+        else
+	        libtorrent_PKG_ERRORS=`$PKG_CONFIG --print-errors --cflags --libs "libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2" 2>&1`
+        fi
+	# Put the nasty error message in config.log where it belongs
+	echo "$libtorrent_PKG_ERRORS" >&5
+
+	as_fn_error $? "Package requirements (libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2) were not met:
+
+$libtorrent_PKG_ERRORS
+
+Consider adjusting the PKG_CONFIG_PATH environment variable if you
+installed software in a non-standard prefix.
+
+Alternatively, you may set the environment variables libtorrent_CFLAGS
+and libtorrent_LIBS to avoid the need to call pkg-config.
+See the pkg-config man page for more details." "$LINENO" 5
+elif test $pkg_failed = untried; then
+        { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+	{ { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "The pkg-config script could not be found or is too old.  Make sure it
+is in your PATH or set the PKG_CONFIG environment variable to the full
+path to pkg-config.
+
+Alternatively, you may set the environment variables libtorrent_CFLAGS
+and libtorrent_LIBS to avoid the need to call pkg-config.
+See the pkg-config man page for more details.
+
+To get pkg-config, see <http://pkg-config.freedesktop.org/>.
+See \`config.log' for more details" "$LINENO" 5; }
+else
+	libtorrent_CFLAGS=$pkg_cv_libtorrent_CFLAGS
+	libtorrent_LIBS=$pkg_cv_libtorrent_LIBS
+        { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; }
+	CXXFLAGS="$libtorrent_CFLAGS $CXXFLAGS" LIBS="$libtorrent_LIBS $LIBS"
+fi
+elif test $pkg_failed = untried; then
+        { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+
+pkg_failed=no
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2" >&5
+printf %s "checking for libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2... " >&6; }
+
+if test -n "$libtorrent_CFLAGS"; then
+    pkg_cv_libtorrent_CFLAGS="$libtorrent_CFLAGS"
+ elif test -n "$PKG_CONFIG"; then
+    if test -n "$PKG_CONFIG" && \
+    { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$PKG_CONFIG --exists --print-errors \"libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2\""; } >&5
+  ($PKG_CONFIG --exists --print-errors "libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2") 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then
+  pkg_cv_libtorrent_CFLAGS=`$PKG_CONFIG --cflags "libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2" 2>/dev/null`
+		      test "x$?" != "x0" && pkg_failed=yes
+else
+  pkg_failed=yes
+fi
+ else
+    pkg_failed=untried
+fi
+if test -n "$libtorrent_LIBS"; then
+    pkg_cv_libtorrent_LIBS="$libtorrent_LIBS"
+ elif test -n "$PKG_CONFIG"; then
+    if test -n "$PKG_CONFIG" && \
+    { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$PKG_CONFIG --exists --print-errors \"libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2\""; } >&5
+  ($PKG_CONFIG --exists --print-errors "libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2") 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then
+  pkg_cv_libtorrent_LIBS=`$PKG_CONFIG --libs "libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2" 2>/dev/null`
+		      test "x$?" != "x0" && pkg_failed=yes
+else
+  pkg_failed=yes
+fi
+ else
+    pkg_failed=untried
+fi
+
+
+
+if test $pkg_failed = yes; then
+        { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+
+if $PKG_CONFIG --atleast-pkgconfig-version 0.20; then
+        _pkg_short_errors_supported=yes
+else
+        _pkg_short_errors_supported=no
+fi
+        if test $_pkg_short_errors_supported = yes; then
+	        libtorrent_PKG_ERRORS=`$PKG_CONFIG --short-errors --print-errors --cflags --libs "libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2" 2>&1`
+        else
+	        libtorrent_PKG_ERRORS=`$PKG_CONFIG --print-errors --cflags --libs "libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2" 2>&1`
+        fi
+	# Put the nasty error message in config.log where it belongs
+	echo "$libtorrent_PKG_ERRORS" >&5
+
+	as_fn_error $? "Package requirements (libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2) were not met:

 $libtorrent_PKG_ERRORS

@ -6119,14 +6272,20 @@ else
				@@ -6119,14 +6272,20 @@ else
 	libtorrent_LIBS=$pkg_cv_libtorrent_LIBS
        { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 printf "%s\n" "yes" >&6; }
-	CXXFLAGS="$libtorrent_CFLAGS $CXXFLAGS"
-                  LIBS="$libtorrent_LIBS $LIBS"
+	CXXFLAGS="$libtorrent_CFLAGS $CXXFLAGS" LIBS="$libtorrent_LIBS $LIBS"
+fi
+else
+	libtorrent_CFLAGS=$pkg_cv_libtorrent_CFLAGS
+	libtorrent_LIBS=$pkg_cv_libtorrent_LIBS
+        { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; }
+	CXXFLAGS="$libtorrent_CFLAGS $CXXFLAGS" LIBS="$libtorrent_LIBS $LIBS"
 fi


 pkg_failed=no
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for openssl" >&5
-printf %s "checking for openssl... " >&6; }
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for openssl >= 1.1.1" >&5
+printf %s "checking for openssl >= 1.1.1... " >&6; }

 if test -n "$openssl_CFLAGS"; then
    pkg_cv_openssl_CFLAGS="$openssl_CFLAGS"
@ -6218,8 +6377,8 @@ fi
				@@ -6218,8 +6377,8 @@ fi


 pkg_failed=no
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for zlib" >&5
-printf %s "checking for zlib... " >&6; }
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for zlib >= 1.2.11" >&5
+printf %s "checking for zlib >= 1.2.11... " >&6; }

 if test -n "$zlib_CFLAGS"; then
    pkg_cv_zlib_CFLAGS="$zlib_CFLAGS"
@ -7845,3 +8004,4 @@ fi
				@@ -7845,3 +8004,4 @@ fi
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: Good, the configure finished." >&5
 printf "%s\n" "$as_me: Good, the configure finished." >&6;}
 printf "%s\n"
+
--- a/configure.ac
+++ b/configure.ac
@ -177,9 +177,11 @@ AC_COMPILE_IFELSE([DETECT_BOOST_VERSION_PROGRAM(106000)], [],
				@@ -177,9 +177,11 @@ AC_COMPILE_IFELSE([DETECT_BOOST_VERSION_PROGRAM(106000)], [],
    [QBT_ADD_DEFINES="$QBT_ADD_DEFINES BOOST_NO_CXX11_RVALUE_REFERENCES"])

 PKG_CHECK_MODULES(libtorrent,
-                  [libtorrent-rasterbar >= 1.2.14],
-                  [CXXFLAGS="$libtorrent_CFLAGS $CXXFLAGS"
-                  LIBS="$libtorrent_LIBS $LIBS"])
+                  [libtorrent-rasterbar >= 2.0.4],
+                  [CXXFLAGS="$libtorrent_CFLAGS $CXXFLAGS" LIBS="$libtorrent_LIBS $LIBS"],
+                  [PKG_CHECK_MODULES(libtorrent,
+                                     [libtorrent-rasterbar >= 1.2.14 libtorrent-rasterbar < 2],
+                                     [CXXFLAGS="$libtorrent_CFLAGS $CXXFLAGS" LIBS="$libtorrent_LIBS $LIBS"])])

 PKG_CHECK_MODULES(openssl,
                  [openssl >= 1.1.1],
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@ -1,12 +1,13 @@
				@@ -1,12 +1,13 @@
+macro(find_libtorrent version)
    if (UNIX AND (NOT APPLE) AND (NOT CYGWIN))
-    find_package(LibtorrentRasterbar QUIET ${minLibtorrentVersion} COMPONENTS torrent-rasterbar)
+        find_package(LibtorrentRasterbar QUIET ${version} COMPONENTS torrent-rasterbar)
        if (NOT LibtorrentRasterbar_FOUND)
            include(FindPkgConfig)
-        pkg_check_modules(LIBTORRENT_RASTERBAR IMPORTED_TARGET GLOBAL "libtorrent-rasterbar>=${minLibtorrentVersion}")
-        if (NOT LIBTORRENT_RASTERBAR_FOUND)
+            pkg_check_modules(LibtorrentRasterbar IMPORTED_TARGET GLOBAL "libtorrent-rasterbar>=${version}")
+            if (NOT LibtorrentRasterbar_FOUND)
                message(
                    FATAL_ERROR
-                "Package LibtorrentRasterbar >= ${minLibtorrentVersion} not found"
+                    "Package LibtorrentRasterbar >= ${version} not found"
                    " with CMake or pkg-config.\n- Set LibtorrentRasterbar_DIR to a directory containing"
                    " a LibtorrentRasterbarConfig.cmake file or add the installation prefix of LibtorrentRasterbar"
                    " to CMAKE_PREFIX_PATH.\n- Alternatively, make sure there is a valid libtorrent-rasterbar.pc"
@ -14,13 +15,13 @@ if (UNIX AND (NOT APPLE) AND (NOT CYGWIN))
				@@ -14,13 +15,13 @@ if (UNIX AND (NOT APPLE) AND (NOT CYGWIN))
                    " to specify additional search paths if needed)."
                )
            endif()
-        add_library(LibtorrentRasterbar::torrent-rasterbar ALIAS PkgConfig::LIBTORRENT_RASTERBAR)
+            add_library(LibtorrentRasterbar::torrent-rasterbar ALIAS PkgConfig::LibtorrentRasterbar)
            # force a fake package to show up in the feature summary
            set_property(GLOBAL APPEND PROPERTY
                PACKAGES_FOUND
-            "LibtorrentRasterbar via pkg-config (version >= ${minLibtorrentVersion})"
+                "LibtorrentRasterbar via pkg-config (version >= ${version})"
            )
-        set_package_properties("LibtorrentRasterbar via pkg-config (version >= ${minLibtorrentVersion})"
+            set_package_properties("LibtorrentRasterbar via pkg-config (version >= ${version})"
                PROPERTIES
                TYPE REQUIRED
            )
@ -28,8 +29,15 @@ if (UNIX AND (NOT APPLE) AND (NOT CYGWIN))
				@@ -28,8 +29,15 @@ if (UNIX AND (NOT APPLE) AND (NOT CYGWIN))
            set_package_properties(LibtorrentRasterbar PROPERTIES TYPE REQUIRED)
        endif()
    else()
-    find_package(LibtorrentRasterbar ${minLibtorrentVersion} REQUIRED COMPONENTS torrent-rasterbar)
+        find_package(LibtorrentRasterbar ${version} REQUIRED COMPONENTS torrent-rasterbar)
+    endif()
+endmacro()
+
+find_libtorrent(${minLibtorrent1Version})
+if (LibtorrentRasterbar_FOUND AND (LibtorrentRasterbar_VERSION VERSION_GREATER_EQUAL 2.0))
+    find_libtorrent(${minLibtorrentVersion})
 endif()
+
 # force variable type so that it always shows up in ccmake/cmake-gui frontends
 set_property(CACHE LibtorrentRasterbar_DIR PROPERTY TYPE PATH)
 find_package(Boost ${minBoostVersion} REQUIRED)