doc: suggest static building for iOS.

doc/building.dox

@@ -532,7 +532,11 @@ platform file, so be sure to properly set **absolute** path to `modules/`
 directory containing `Platform/iOS.cmake`. Set `CMAKE_INSTALL_PREFIX` to prefix
 where you store other iOS dependencies such as Corrade or SDL2.
 
-OpenGL ES 2.0 is enabled by default, switch to 3.0 by disabling `TARGET_GLES2`.
+As every application is in its own sandbox, it doesn't make sense to build
+shared libraries (although it is supported). Enable `BUILD_STATIC` to build
+static libraries. You might also have problems using dynamic plugins, enable
+`BUILD_PLUGINS_STATIC` to build also plugins as static. OpenGL ES 2.0 is
+enabled by default, switch to 3.0 by disabling `TARGET_GLES2`.
 
     mkdir build-ios && cd build-ios
     cmake .. \
@@ -541,6 +545,8 @@ OpenGL ES 2.0 is enabled by default, switch to 3.0 by disabling `TARGET_GLES2`.
         -DCMAKE_OSX_SYSROOT=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS.sdk \
         -DCMAKE_OSX_ARCHITECTURES="arm64;armv7;armv7s" \
         -DCMAKE_INSTALL_PREFIX=~/ios-libs \
+        -DBUILD_STATIC=ON -DBUILD_PLUGINS_STATIC=ON \
+        -DTARGET_GLES2=OFF \
         -DWITH_SDL2APPLICATION=ON \
         -G Xcode
     cmake --build .