AppImage: Allow unset VCPKG_LIB_PATH variable

Only if you're building on Linux with vcpkg should you worry about
having to set this variable.

Signed-off-by: Avery King <[email protected]>

BUILDING.md

@@ -290,10 +290,10 @@ You can build an AppImage yourself. This requires that you have previously
 built Tenacity. Note that you do not need to have installed Tenacity in order
 to make an AppImage as it is unnecessary.
 
-First, you need to set `VCPKG_LIB_PATH` to the directory vcpkg copied libraries
-too if you are using vcpkg. If not, set this to an empty string. Next, run
-`cpack` from the root of your build directory. The AppImage will be in the
-`package/` directory of the build folder.
+First, if you are using vcpkg, you need to set `VCPKG_LIB_PATH` to the
+directory vcpkg copied libraries too. Otherwise, setting this variable is not
+necessary. Next, run `cpack` from the root of your build directory. The
+AppImage will be in the `package/` directory of the build folder.
 
 ## Build options
 

linux/create_appimage.sh

@@ -91,6 +91,13 @@ ln -sf share/icons/hicolor/scalable/apps/tenacity.svg "${appdir}/.DirIcon"
 # Bundle dependencies
 #============================================================================
 
+# VCPKG_LIB_PATH is the path where vcpkg stores built libraries
+# FIXME: Come up with a solution in CMake instead or something.
+if [[ -z "${VCPKG_LIB_PATH}" ]];
+then
+   VCPKG_LIB_PATH=""
+fi
+
 # HACK: Some wxWidget libraries depend on themselves. Add
 # them to LD_LIBRARY_PATH so that linuxdeploy can find them.
 export LD_LIBRARY_PATH="${appdir}/usr/lib/tenacity:${VCPKG_LIB_PATH}:${LD_LIBRARY_PATH-}"