chore: add a note about compiling libseccomp from scratch

We need to compile it from source because version provided by the
distribution is not compiled with musl-gcc.

Signed-off-by: Egor Lazarchuk <yegorlz@amazon.co.uk>

tools/devctr/Dockerfile

@@ -149,6 +149,10 @@ RUN cd /usr/include/$ARCH-linux-musl \
     && ln -s ../asm-generic asm-generic
 
 # Install static version of libseccomp
+# We need to compile from source because 
+# libseccomp provided by the distribution is not
+# compiled with musl-gcc and we need this
+# for our musl builds.
 #
 RUN apt-get update \
     && apt-get -y install \