drop ocaml on i386, it makes no sense to support it in Ubuntu, where i386 is disabled.

(In Debian we have no rdeps, i386 as host is not used anymore, and ocaml support is on a subset of architectures anyway)

debian/control

@@ -14,10 +14,10 @@ Build-Depends: debhelper (>= 9.0), cmake, chrpath, texinfo, sharutils,
     g++-multilib [amd64 i386 kfreebsd-amd64 mips mips64 mips64el mipsel powerpc ppc64 s390 s390x sparc sparc64 x32],
     libjs-mathjax, python3-recommonmark,
     doxygen, gfortran,
-    ocaml-nox [amd64 arm64 armhf i386 ppc64el s390x],
-    ocaml-findlib [amd64 arm64 armhf i386 ppc64el s390x],
-    libctypes-ocaml-dev [amd64 arm64 armhf i386 ppc64el s390x],
-    dh-exec, dh-ocaml [amd64 arm64 armhf i386 ppc64el s390x],
+    ocaml-nox [amd64 arm64 armhf ppc64el s390x],
+    ocaml-findlib [amd64 arm64 armhf ppc64el s390x],
+    libctypes-ocaml-dev [amd64 arm64 armhf ppc64el s390x],
+    dh-exec, dh-ocaml [amd64 arm64 armhf ppc64el s390x],
     libpfm4-dev [linux-any], python3-setuptools, libz3-dev
 Build-Conflicts: oprofile, ocaml
 Standards-Version: 4.2.1
@@ -378,7 +378,7 @@ Description: Modular compiler and toolchain technologies, tools
 
 Package: libllvm-10-ocaml-dev
 Section: ocaml
-Architecture: amd64 arm64 armhf i386 ppc64el s390x
+Architecture: amd64 arm64 armhf ppc64el s390x
 Suggests: llvm-10-doc
 Depends: ${shlibs:Depends}, ${misc:Depends}, ${ocaml:Depends}, llvm-10-dev (= ${binary:Version})
 Replaces: libllvm-x.y-ocaml-dev

debian/rules

@@ -260,7 +260,7 @@ endif
 
 DH_OPTIONS=
 OCAML_ENABLE= no
-OCAML_ARCHS := amd64 arm64 armhf i386 ppc64el s390x
+OCAML_ARCHS := amd64 arm64 armhf ppc64el s390x
 ifneq (,$(filter $(DEB_HOST_ARCH),$(OCAML_ARCHS)))
 # Enable OCAML for this arch.
 	OCAML_ENABLE=yes